Chitosan and polyethylene glycol copolymers and methods and devices for using same for sealing a vascular puncture

ABSTRACT

A sealant is provided for sealing a puncture through tissue that comprises an elongate first section including a proximal end, a distal end, and a cross-section sized for delivery into a puncture through tissue, and a second section extending from the distal end of the first section. The first section may be formed from a freeze-dried hydrogel that expands when exposed to physiological fluid within a puncture. The first section comprises chitosan and at least one additional polymer. The second section may be formed from a solid mass of non-freeze-dried, non-cross-linked hydrogel precursors. The precursors are in an unreactive state until exposed to an aqueous physiological environment, whereupon the precursors undergo in-situ crosslinking with one another to provide an adhesive layer bonded to the first section. The second section may further comprise chitosan. Apparatus and methods for delivering the sealant into a puncture through tissue are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 14/724,591 filed on May 28, 2015, titled “CHITOSANAND POLYETHYLENE GLYCOL COPOLYMERS AND METHODS AND DEVICES FOR USINGSAME FOR SEALING A VASCULAR PUNCTURE”, which claims priority to U.S.Provisional Patent Application No. 62/004,806 filed on May 29, 2014,titled “CHITOSAN AND POLYETHYLENE GLYCOL COPOLYMERS AND METHODS ANDDEVICES FOR USING SAME FOR SEALING A VASCULAR PUNCTURE”.

FIELD

Several embodiments of the inventions disclosed herein relate generallyto sealants, apparatus, and methods for sealing punctures in a body.Some embodiments relate to copolymers that provide enhanced sealingeffects. In several embodiments, apparatus and methods are disclosedthat employ such copolymers for sealing a vascular puncture extendingthrough tissue to a blood vessel.

BACKGROUND

Apparatus and methods are known for accessing a patient's vasculaturepercutaneously, e.g., to perform a procedure within the vasculature, andfor sealing the puncture that results after completing the procedure.For example, a hollow needle may be inserted through a patient's skinand overlying tissue into a blood vessel. A guide wire may be passedthrough the needle lumen into the blood vessel, whereupon the needle maybe removed. An introducer, procedural, or femoral sheath may then beadvanced over the guide wire into the vessel, e.g., in conjunction withor subsequent to one or more dilators. A catheter or other device may beadvanced through the introducer sheath and over the guide wire into aposition for performing a medical procedure. Thus, the introducer sheathmay facilitate accessing and/or introducing various devices into thevessel, while minimizing trauma to the vessel wall and/or minimizingblood loss.

Wounds such as arteriotomies can arise in the blood vessel from thesevarious medical procedures, especially for blood vessels acting as sitesfor catheter insertion during diagnostic and/or interventionalcatheterization. After such procedures have been completed, thearteriotomy that was created as an access point during the medicalprocedure needs to be closed.

Upon completing the procedure, the device(s) and introducer sheath maybe removed, leaving a puncture extending between the skin and the vesselwall. To seal the puncture, external pressure may be applied to theoverlying tissue, e.g., manually and/or using sandbags, until hemostasisoccurs. This procedure, however, may be time consuming and expensive,requiring as much as an hour of a medical professional's time. It isalso uncomfortable for the patient, and may require the patient toremain immobilized in the operating room, catheter lab, or holding area.In addition, a risk of hematoma exists from bleeding before hemostasisoccurs.

Vascular closure devices can be used to achieve hemostasis (e.g.,sealing) of small holes that are formed in a blood vessel (either arteryor vein) as the result of an intravascular procedure (e.g.,cannulation). Such procedures may be for diagnosis, drug delivery,therapy (e.g., stent placement or angioplasty) and the like. Theprocedures involve the formation of a small incision in the wall of avessel to gain access to the intravascular space. This incision, thevascular puncture or arteriotomy, must be closed at the completion ofthe procedure. Rapid hemostasis at the vascular puncture is ideal, as itreduces patient complications, improves time to patient ambulation andtime to hospital discharge.

For example, a mechanical based device can be utilized for vascularclosure. A percutaneous surgical device can comprise a combination woundsuturing and crimping and cutting device. The combined device may locatea vessel wound and pass suture through the vessel walls surrounding thewound. Then, the crimping and cutting portion may detach, the suturingportion may be removed, and the crimping and cutting portion may belocated to the wound site to apply a fastener (e.g., a ferrule).

Another mechanical based device can have two components: a needleadvancing apparatus slidable longitudinally along a catheter to advanceneedles into a tissue membrane, such as a blood vessel wall, around anopening in the membrane; and, a suture retrieval assembly insertablethrough the catheter beyond a distal side of the tissue membrane. Theneedle advancing apparatus advances suture through the tissue wall. Thesuture retrieval assembly grabs the suture on the distal side of thetissue membrane for extraction thereof through the opening in the tissuemembrane.

Such mechanical approaches tend to require precise positioning withinthe tissue tract, typically provide point (instead of a continuum oftissue purchase) support, and lead to permanent foreign-body implantsthat interfere with subsequent catheterization at the same vascularsite. Additionally, a purely mechanical support of the wound could leadto implanting substantially non-absorbable foreign material thatprovides only point-support to the wound lips. In addition, purelymechanical closures still can leave behind open micro-spaces, or smallgaps, between the sutures that are not entirely closed.

Previously (and currently, in some cases), manual compression was themain method for closing the vascular puncture. This could involveextended periods of manual pressure, clamping, exogenous weights, etc.,applied directly to the site of the vascular puncture. As hemostasiscould take 20 to 60 minutes, patients often experienced discomfort, andextended periods of bed rest were required.

In addition to, or in place of manual compression, vascular closuredevices were developed to reduce the time to achieve hemostasis. Somesuch devices used sutures or collagen plugs to seal the vascularpuncture. However, many such devices result in an intravascularcomponent being retained within the vessel, which can lead to futurecomplications.

More recently biodegradable materials have been employed to seal thevascular puncture and, due to their dissolution over time, improvepatient comfort and reduce complications. Because rapid hemostasis canimprove patient outcome and reduce medical costs, further improvementsin vascular sealants would be beneficial.

Though presently in use, many current sealant technologies facilitatehemostasis of a wound puncture by physically clogging the tissue tract.This physical occlusion replaces manual compression, but certain of suchpolymeric sealants have a relatively weak polymer network integrity,which can increase time to hemostasis.

Various biological approaches to vascular closure have been used such asa device and method that includes inserting a vessel plug or sealantinto the incision or puncture until the distal end of the vessel plug isadjacent to the outer lumen of the blood vessel. The vessel plug ispositioned so that it does not obstruct the flow of fluid through theblood vessel or target organ. The precise positioning of the vessel plugin the incision or puncture is accomplished through the use of a ballooncatheter or a cylindrical insertion assembly having a proximal plungermember associated therewith. Another biological closure can deploy acollagen plug to seal the closure. In order to block the collagen fromentering the vessel, a footplate is installed on the interior of theblood vessel. The footplate is held in place with a suture.

In one instance, a vascular closure device can include two syntheticpolyethylene glycol (“PEG”) polymer powders that are mixed withappropriate buffers and injected through a femoral sheath at anarteriotomy site, e.g., as disclosed in U.S. Pat. No. 7,316,704.Accordingly, apparatus and methods for sealing a puncture through tissuewould be useful. In particular, improving the efficacy (e.g., speedand/efficiency) of sealing a puncture would be useful.

SUMMARY

Provided for herein, in several embodiments, are vascular sealants,apparatus, and methods for sealing vascular punctures, the vascularsealants comprising copolymers that provide enhanced sealing effects.

As such, several embodiments herein provide vascular sealants comprisingcopolymers that provide enhanced hemostasis. In some embodiments, thisis due to supplementation of the physical occlusion of the vascularpuncture by sealants that have hemostatic and/or procoagulativeproperties. In several embodiments, the sealants attract plateletsand/or other coagulation promoting co-factors. In several embodiments,the copolymer sealants provide enhanced “grip” at the site of a vascularpuncture, thereby improving the occlusion of the puncture, and evenallow the use of the copolymer sealants on larger puncture sizes.

In several embodiments, the copolymer sealant comprises chitosan and oneor more polyethylene glycol polymers that exhibits a more rapidhemostasis compared to sealants that comprise only chitosan or onlypolyethylene glycol polymer sealants. Chitosan is a natural biopolymerfound in crustaceans with a wide range of applications in tissueengineering, tissue repair and wound healing. Chitosan can be producedby deacetylation of chitin, which is the structural element in theexoskeleton of crustaceans (e.g., crabs, shrimps, etc.). Variation inthe degree of deacetylation (% DA) can result in varying functionalityof the chitosan in different applications. Chitosan is alsobiodegradable, for example, by chitosanase, papain, cellulose, acidproteases, and the like. Chitosan can form hydrogels depending on themolecular weight, the degree of deacetylation and the pH. In addition, avariety of cross linkers can be utilized to crosslink chitosan polymerchains and result in the formation of hydrogels.

Chitosan has been known to have hemostatic properties, which aredescribed, for example in U.S. Pat. No. 4,394,373 and U.S. Pat. No.8,012,167. However, in several embodiments, the chitosan of thecopolymer sealants disclosed herein, is not simply mixed with the otherpolymeric component (or components), but rather is bound (e.g.,covalently or non-covalently) to the other component (or components) ofthe sealant. For example, in several embodiments, the copolymer sealantcomprises chitosan covalently (or non-covalently) bound to two types ofpolyethylene glycol (PEG), PEG-amine and PEG-ester. Advantageously, thisimproves the structural integrity of the sealant when deployed, but alsoimparts pro-coagulant and hemostatic properties to the sealant thatimprove efficacy in sealing vascular punctures.

Several embodiments of the sealants disclosed herein comprise bothpolyethylene glycol and chitosan in the freeze dried polymer hydrogel(e.g., the sealant). Sealants comprising only PEG (with no chitosanincorporated) elicit hemostasis of a wound puncture essentially byclogging the tissue tract upon expansion of the hydrogel sealant in thepresence of physiological fluids. Freeze dried hydrogel sealantcontaining only PEG would lack the hemostatic and pro-coagulativeproperties of chitosan that is included in the sealants disclosed hereinand thus PEG-only sealants would result in slower and less efficienthemostasis.

On the other hand a freeze dried hydrogel sealant utilizing chitosanonly (with no PEG components incorporated) would lack the porositycharacteristics (size and number of pores) that partially cross-linkedPEG hydrogels can create upon freeze drying. Such a hydrogel would lackthe rapid swelling capability that PEG components impart. Thesehydrogels would have reduced capacity to absorb physiological fluids andswell and subsequently clog the tissue tract. In addition thesehydrogels would have reduced capacity to rapidly absorb blood andindirectly boost the inherit capability of chitosan since less bloodwould be available for chitosan to promote clotting. This would resultin a reduced capacity to promote hemostasis as compared to hydrogelsthat contain both polyethylene glycol and chitosan, such as thosedisclosed herein.

Thus, freeze dried hydrogels comprising both chitosan and polyethyleneglycol advantageously, and unexpectedly, lead to faster hemostasis ofwounds since they combine the swelling characteristics of the PEG moietyalong with the hemostatic and pro-coagulative properties of chitosan.The absorbance of blood by the porous PEG components can supplement andenhance chitosans ability for clotting because more blood volume isavailable for chitosan per surface area. These chitosan-PEG hydrogelsmay therefore have application to larger wounds versus the limitedapplicability when the sealant is composed of only polyethylene glycolor only chitosan.

Therefore, there are provided, in several embodiments, sealants forsealing punctures in tissues. In one embodiment, there is provided asealant for sealing a puncture through tissue, comprising an elongatefirst section having a proximal end, a distal end, and a cross-sectionsized for delivery into a puncture through tissue and a second sectionextending from the distal end of the first section, the first sectioncomprising a hydrogel comprising chitosan bound to at least one polymer.In several embodiments, the first section is formed from a freeze-driedhydrogel and the first section is configured to expand when exposed tophysiological fluid within a puncture. In several embodiments, uponexposure to an aqueous physiological fluid, the hydrogel expands andseals the puncture through the tissue. In several embodiments, thepuncture is a vascular puncture.

Also provided, in several embodiments, is a sealant for sealing apuncture through tissue, comprising a first section formed from afreeze-dried hydrogel, the first section being configured to expand whenexposed to physiological fluid within a puncture. In severalembodiments, the first section comprises a hydrogel comprising chitosanbound to at least one polymer, and upon exposure to an aqueousphysiological fluid, the hydrogel expands and seals the puncture throughthe tissue.

In several embodiments, the first section has an elongated shape with aproximal end, a distal end, and a cross-section sized for delivery intoa puncture through tissue. In several embodiments, the chitosancomprises chitosan that is at least partially deacetylated. For example,in one embodiment, the chitosan has a degree of deacetylation of atleast 60%. In additional embodiments, the degree of deacetylation isbetween about⁴⁰⁰ to 50%, about 50% to about 60 about 60% to about 700about 70% to about 80%, about 80% to about 90%, about 90% to about 95%,about 95% to about 99% (and overlapping ranges between those listed).Greater or lesser degrees of deacetylation are also used, in otherembodiments.

In several embodiments, the chitosan has a molecular weight betweenabout 10 kilodaltons and about 600 kilodaltons, including about 10kilodaltons to about 50 kilodaltons, about 50 kilodaltons to about 100kilodaltons, about 100 kilodaltons to about 200 kilodaltons, about 200kilodaltons to about 300 kilodaltons, about 300 kilodaltons to about 400kilodaltons, about 400 kilodaltons to about 500 kilodaltons, about 500kilodaltons to about 600 kilodaltons, or any molecular weight between orincluding those values.

Depending on the embodiment, the chitosan can be of a varied type. Forexample, in several embodiments, the chitosan can be free chitosan,chitosan chloride, chitosan glutamate, chitosan acetate, chitosandicarboxylic acid salts, chitosan adipate, chitosan succinate, orchitosan fumarate. In some embodiments, combinations of two or moreforms of chitosan are used.

In several embodiments, the at least one polymer is a polyethyleneglycol polymer chain. In some embodiments, the at least one polymer is apolyethylene glycol polymer chain with side group functionality. Inseveral embodiments, the at least one polymer is an amine modifiedpolyethylene glycol or an ester modified polyethylene glycol.Combinations of amine modified polyethylene glycols and ester modifiedpolyethylene glycols can also be used, in several embodiments. Inseveral embodiments, the chitosan is bound to the at least one polymerby a covalent bond. In additional embodiments, the chitosan is bound tothe at least one polymer by a non-covalent bond. In one embodiment, theat least one polymer is cross-linked polyethylene glycol that is boundto the chitosan.

In several embodiments, the amount of chitosan is varied. For example,in several embodiments, the first section of the sealant comprisesbetween about 0.1% and about 30% (by weight) chitosan. For example, inseveral embodiments the chitosan is present in an amount (by weight)between about 0.1% to about 1.0%, about 1.0% to about 5.0%, about 5.0%to about 10.0%, about 10.0% to about 15.0%, about 15.0% to about 20.0%,about 20.0% to about 25.0%, about 25.0% to about 30.0%, and any amountbetween or including those amounts. In one embodiment the first sectioncomprises between about 0.5% and about 8% (by weight) chitosan. In oneembodiment, the first section comprises between about 2% and about 4%(by weight) chitosan. In one embodiment, the first section comprisesbetween about 4% and about 6% (by weight) chitosan. Greater or lesseramounts of chitosan are also used, in some embodiments.

In several embodiments, the at least one polymer comprises polyethyleneglycol-amine (PEG-amine) and polyethylene glycol-ester (PEG-ester). Insome embodiments, the PEG-amine and PEG-ester are present in a molarratio of PEG-amine to PEG-ester between 4 to 1 and 1 to 4. In someembodiments, the PEG-amine and PEG-ester are present in a molar ratio ofPEG-amine to PEG-ester between 2 to 1 and 1 to 2. In some embodiments,the PEG-amine and PEG-ester are present in a molar ratio of PEG-amine toPEG-ester between about 0.8 to about 1.2. In some embodiments, thePEG-amine and PEG-ester are present in a molar ratio of PEG-amine toPEG-ester between about 0.9 to about 1.

In several embodiments, the PEG-amine and PEG-ester are present in aratio of equivalent active groups that ranges from about 0.1 to about 5.In some embodiments, the PEG-amine and PEG-ester are present in a ratioof equivalent active groups that ranges from about 0.5 to about 3. Insome embodiments, the PEG-amine and PEG-ester are present in a ratio ofequivalent active group sites that ranges from between about 0.5 toabout 2.0. In some embodiments, the PEG-amine and PEG-ester are presentin a ratio of equivalent active group sites that ranges from about 0.8to about 1.2. In some embodiments, the PEG-amine and PEG-ester arepresent in a ratio of equivalent active group sites that ranges fromabout 0.9 to about 1.

In several embodiments, the at least one polymer comprises polyethyleneglycol-ester (PEG-ester). In one embodiment, the PEG-ester can bepresent in an amount (by weight) between about 99.0% to about 1.0%,about 90.0% to about 10.0%, about 80.0% to about 20.0%, about 70.0% toabout 30.0%, about 60.0% to about 40.0%, about 55.0% to about 45.0,about 53.0% to about 47.0%, about 52.0% to about 48.0%, about 52.0% toabout 50.0%, and any amount between or including those amounts.

In several embodiments, the at least one polymer comprises polyethyleneglycol-amine (PEG-amine) and a mixture of polyethylene glycol-esters(PEG-esters). In some embodiments, the PEG-amine and PEG-ester mixturecan be present in a molar ratio of PEG-amine to PEG-ester of between 4to 1 and 1 to 4. In some embodiments, the PEG-amine and PEG-estermixture can be present in a molar ratio of PEG-amine to PEG-esterbetween 2 to 1 and 1 to 2. In some embodiments, the PEG-amine andPEG-ester can be present in a molar ratio of PEG-amine to PEG-esterbetween about 0.8 to about 1.2. In some embodiments, the PEG-amine andPEG-ester can be present in a molar ratio of PEG-amine to PEG-esterbetween about 0.9 to about 1.

In several embodiments, the sealant can also include a second section.In some embodiments, the second section can extend from the distal endof the first section. In some such embodiments, the second section canbe made up of non-cross-linked precursors. In some embodiments, thenon-cross-linked precursors comprise polyethylene glycol-amine and/orpolyethylene glycol-ester. Depending on the embodiments, the secondsection also optionally includes chitosan. For example, in oneembodiment, the second section can be a mixture of non-cross-linkedpolyethylene glycols bound to the chitosan. In several embodiments, thesecond section (when chitosan is included) can include between about0.1% and about 30% (by weight) chitosan. For example, the second sectionmay, in some embodiments, include between about 0.1% and about 30% (byweight) chitosan, including about 0.1% to about 1%, about 1.0% to about5.0%, about 5% to about 10.0%, about 10.0% to about 15.0%, about 15.0%to about 20.0%, about 20.0% to about 25.0%, about 25.0% to about 30.0%,and any amount between or including those amounts.

Also, in several embodiments, the second section may also include one ormore reinforcement elements. In some embodiments, the reinforcementelements have hemostatic properties including but not limited tochitosan reinforcing fibers, chitosan mesh, chitosan particles, orcombinations thereof.

In several embodiments, the chitosan mesh is configured as a helicalcoil within the second section. In several embodiments, the chitosanmesh (regardless of its conformation) includes cross-linked chitosan,wherein the cross-links were formed using genipin. In severalembodiments, chitosan fibers are configured as a helical coil within thesecond section. In some such embodiments, the chitosan fibers are formedby electrospinning. In several embodiments, the chitosan can be in theform of particles that are incorporated into the second section. Thechitosan particles can be incorporated, depending on the embodiment, ina random manner throughout the second section, in a substantiallyuniform manner throughout the second section, or a patterned mannerthroughout the second section. In additional embodiments, random,uniform, or patterned particle distribution can be used in differentportions of the second section.

In several embodiments, the sealant can be configured to seal a vascularpuncture, wherein the sealant expands after exposure to an aqueousphysiological fluid, and wherein a second section of the sealant canhave hemostatic and pro-coagulative properties. In several embodiments,the second section further comprises a pH adjusting agent. In severalembodiments, the sealant further comprises a therapeutic agent. Inseveral embodiments, the sealant is dimensioned with a first sectionhaving a length (e.g., between proximal and distal ends) of betweenabout 1 and about 20 millimeters. In several embodiments including asecond section, the second section has a length of between about 0.5 andabout 5 millimeters.

In several embodiments having both first and second sections, the firstand second sections can have a substantially uniform outer cross-sectionalong their lengths between about 1 and about 8 millimeters. Uponexposure to an aqueous physiological fluid, the sealants are configuredto expand. In some embodiments, the first section (and second section,if included) is configured to expand in the dimension of the outer crosssection of the sealant of at least 15%, including at least 20%, at least25%, at least 30%, at least 40%, or at least 50%.

There are also provided herein methods for sealing a vascular puncturecomprising applying a sealant as described herein to the vascularpuncture.

In several embodiments, therefore, there are provided sealants andassociated methods for sealing a puncture in a body. More particularly,several embodiments are directed to sealants made from chitosan andpolyethylene glycol for sealing a puncture through tissue, and tomethods for making such sealants. In addition, several embodiments ofthe invention are directed to sealants and methods for providingtemporary or permanent hemostasis within a puncture extending throughtissue.

In accordance with one embodiment, a sealant is provided for sealing apuncture through tissue that includes a first section including aproximal end, a distal end, and a cross-section sized for delivery intoa puncture through tissue, and a second section fused to and extendingfrom the distal end of the first section. In several embodiments, thefirst section is formed from a freeze-dried hydrogel made of chitosanand polyethylene glycol polymer chains and/or crosslinks that expandswhen exposed to physiological fluid within a puncture. In severalembodiments, the second section is formed from a solid mass ofnon-freeze-dried, non-cross-linked hydrogel precursors, the precursorsremaining in an unreactive state until exposed to an aqueousphysiological environment, whereupon the precursors undergo in-situcrosslinking with one another to provide an improved adhesion of thesealant to the arteriotomy.

In one embodiment, the first section may consist essentially offreeze-dried hydrogel, and the second section may consist essentially ofthe non-cross-linked precursors. Alternatively, the second section mayinclude one or more reinforcement elements with hemostatic properties,e.g., chitosan reinforcing fibers, a chitosan mesh or chitosanparticles. In addition or alternatively, the second section may includeone or more diluents to enhance one or more properties of the secondsection.

In another embodiment, the sealant includes only one section of afreeze-dried hydrogel made of chitosan and polyethylene glycol polymerchains and/or crosslinks that expands when exposed to physiologicalfluid within a puncture.

Optionally, the sealant may include one or more pH adjusting agents,e.g., impregnated into, coated over, or otherwise included in the firstand/or second sections. For example, when the sealant is exposed withina puncture, the agent(s) may alter the localized pH on or around thesealant, e.g., to enhance cross-linking of the precursors and/orcreation of a desired adhesive material. Alternatively, the materialsfor the precursors may be selected such that the pH and/or bufferingcapacity of interstitial body fluids and/or blood are effective to driveor otherwise facilitate cross-linking of the precursors. In suchembodiments, the pH adjusting agents may be omitted.

In several embodiments, the first section of the sealant may be composedof a freeze-dried hydrogel that contains polyethylene glycol chainscovalently bonded with chitosan polymer chains that has hemostatic andpro-coagulative properties and that expands when exposed tophysiological fluids within a puncture. A solid mass of non-cross-linkedhydrogel precursors such as polyethylene glycol with ester end groups,polyethylene glycol with amine end groups and chitosan with variousdegrees of deacetylation, may be fused or otherwise attached onto thedistal end of the sealant. Until such time that the precursors areexposed to an aqueous physiological environment, the precursors remainin an unreactive state. At such time, the precursors undergo in-situcrosslinking with one another to provide an improved adhesion to thearteriotomy.

In an additional embodiment, chitosan fibers, chitosan mesh or chitosanparticles may be incorporated or fused together with thenon-cross-linked hydrogel precursors. For example, the solid mass may beformed as a substantially uniform solid plug or may be formed as asintered mass of powder and fibers or mesh. The chitosan fibers, mesh orparticles may act as a reinforcement element to increase the integrityof the cross-linked network. The melted precursors, which may or may notcomprise chitosan fibers, chitosan mesh or chitosan particles may beapplied to the distal end of the tubular roll within the tubular member,and allowed to solidify to create the solid mass fused to the distal endof the tubular roll.

In accordance with one embodiment, a sealant is provided for sealing apuncture through tissue that includes a first section including aproximal end, a distal end, and a cross-section sized for delivery intoa puncture through tissue, and a second section fused to and extendingfrom the distal end of the first section. The first section may beformed from a freeze-dried hydrogel that expands when exposed tophysiological fluid within a puncture. The second section may be formedfrom a solid mass of non-freeze-dried, non-cross-linked hydrogelprecursors, the precursors remaining in an unreactive state untilexposed to an aqueous physiological fluid, whereupon the precursorsundergo in-situ crosslinking with one another to provide an improvedadhesion of the sealant to the arteriotomy.

In one embodiment, the first section may consist essentially offreeze-dried hydrogel, and the second section may consist essentially ofthe non-cross-linked precursors. Alternatively, the second section mayinclude one or more reinforcement elements, e.g., a plurality offilaments or particles, mixed with, embedded in, or surrounding theprecursors. In addition or alternatively, the second section may includeone or more diluents to enhance one or more properties of the secondsection. As discussed above, the sealant may (or may not) include one ormore pH adjusting agents, e.g., impregnated into, coated over, orotherwise included in the first and/or second sections.

In another embodiment, a sealant is provided for sealing percutaneousvascular large bore punctures, the sealant includes a first sectionincluding a proximal end, a distal end, and a cross-section sized fortranscatheter delivery into the tissue tract and further includingchitosan, and can optionally include a second section fused to andextending from the distal end of the first section. The large borepunctures can be sealed with a sealant that is initially sized the sameas or larger than the large bore puncture or, alternatively, can besealed with a sealant that is initially sized smaller than the largebore puncture by being loaded onto a small bore delivery device. It isunderstood that the physical properties of the sealant are such that itexpands to occupy the full space of the device it is loaded upon, suchthat the same size sealant can be loaded onto a large bore deliverydevice as well as a small bore delivery device, just that upon beingloaded onto a small bore delivery device the sealant would be compressedto fit into the smaller space. Large bore punctures can be arterialpunctures that are sized from about 7 French to about 24 French. It istypically understood that small bore punctures can be arterial puncturessized up to about 7Fr.

BRIEF DESCRIPTION OF THE DRAWINGS

It will be appreciated that the drawings are not necessarily drawn toscale, with emphasis instead being placed on illustrating the variousaspects and features of the illustrated embodiments.

FIG. 1 is a perspective view of an exemplary embodiment of a sealantmember comprising a freeze-dried hydrogel made of chitosan andpolyethylene glycol polymer chains and/or crosslinks that expands whenexposed to physiological fluid within a puncture.

FIG. 1A is a cross-sectional view of a transfer tube and mandrel,showing a method for making the sealant member of FIG. 1.

FIGS. 2A and 2B are side views of various embodiments in which chitosanis incorporated into a sealant. FIG. 2A shows as chitosan mesh, whileFIG. 2B shows chitosan particles.

FIGS. 3A and 3B are perspective and side views, respectively, of anotherembodiment of an apparatus for delivering a sealant into a puncturethrough tissue.

FIG. 3C is a side view of the apparatus of FIGS. 3A and 3B with aportion of an outer housing removed to show internal components of theapparatus.

FIG. 3D is a perspective view of an introducer sheath and dilatorassembly that may be used in cooperation with the apparatus of FIGS.3A-3C.

FIG. 4A-4F illustrate a method of delivering a sealant to an arteriotomysite.

FIGS. 5A, 5A-1, 5B, and 5B-1 illustrate a mechanism for controllingfluid flow through an inflation line.

FIGS. 6A, 6A-1, 6B, and 6B-1 illustrate another mechanism forcontrolling fluid flow through an inflation line.

FIGS. 6C-6D illustrate yet another mechanism for controlling fluid flowthrough an inflation line.

FIGS. 6E-6F illustrate yet another mechanism for controlling fluid flowthrough an inflation line.

FIGS. 7A, 7A-1, 7B, and 7B-1 illustrate yet another mechanism forcontrolling fluid flow through an inflation line.

FIGS. 8A-8B illustrate a mechanism for controlling movement of an outerhousing relative to an inner housing.

FIGS. 9A-9B illustrate another mechanism for controlling movement of anouter housing relative to an inner housing.

FIGS. 10A-10B illustrate yet another mechanism for controlling movementof an outer housing relative to an inner housing.

FIGS. 11A-11C illustrate a locking mechanism to prevent actuation of asupport member.

FIGS. 12A-12B illustrate a mechanism for advancing a support member.

FIGS. 13A-13B illustrate another mechanism for advancing a supportmember.

FIGS. 14A-14B illustrate a retraction lock to restrict movement of apositioning assembly.

FIGS. 15A-15F illustrate another method for delivering a sealant to anarteriotomy site.

FIGS. 16A-16B illustrate an apparatus for delivering a sealant to anarteriotomy including an inflation indicator.

FIGS. 17A-17D illustrate an embodiment of a dilator configured to engagea sheath.

FIGS. 18A-18C illustrate another embodiment of a dilator configured toengage a sheath.

FIGS. 19A-19D-1 illustrate a mechanism for engaging a positioningassembly and a sheath.

FIG. 20 illustrates another mechanism for engaging a positioningassembly and a sheath.

FIGS. 21A-21I illustrate a method for delivering a sealant to anarteriotomy site.

DETAILED DESCRIPTION

The apparatus, sealant and method disclosed herein capitalize on theinteractions between chitosan and PEG moieties (e.g., PEG-amine andPEG-ester) to achieve enhanced hemostatic and procoagulative propertieswith improved integrity of the cross-linked sealant (both the grip andthe freeze dried portion) after activation by physiological fluids.Chitosan can be covalently or non-covalently bonded, depending on theembodiment, with PEG to create the sealants. In addition, various crosslinkers (e.g., genipin) can be used to crosslink chitosan polymer chainsto create high molecular weight hydrogels of pure chitosan. Thehydrogels can then be dehydrated by freeze drying to make a porous meshthat can be incorporated in the second section (the “grip” section) of asealant to improve the integrity and stability of the final cross-linkednetwork (after contact with physiological fluids). Sealants

FIG. 1 shows a non-limiting embodiment of a sealant 2 for sealing apuncture extending through tissue (not shown), such as a blood vessel.Generally, the sealant 2 can include a first, proximal, or main section4 including proximal and distal ends 4 a, 4 b, and a second, distal, ortip section 6 formed from a plurality of non-freeze-dried and/ornon-cross-linked precursors, e.g., formed as a solid mass or solid plug,fused or otherwise attached to and extending distally from the distalend 4 b of the first section 4. As described further below, thenon-cross-linked precursors may remain in an unreactive state, e.g.,before or until exposure to an aqueous physiological environment, e.g.,when deployed or otherwise exposed within a puncture extending throughtissue.

For example, this configuration of sealant 2 may combine crosslinking ofthe second section 6 to create an adhesive material in-situ with swellcharacteristics and pro-coagulative properties of a freeze-driedhydrogel or other expandable material of the first section 4. Byincorporating chitosan into a polyethylene glycol polymer network, theoverall freeze dried hydrogel results in unexpectedly enhancedextra-vascular closure by providing expansion of the freeze driedhydrogel within the tissue tract upon contact with physiological fluidand providing hemostatic and pro-coagulative properties that, incombination, result in faster overall hemostasis of the vessel.

In one embodiment, the first section 4 can be formed from a sheet offreeze-dried hydrogel rolled into a tubular shape. It will beappreciated that the first section 4 may have other tubular or solid rodcross-sections or shapes, as desired, such as elliptical, triangular,square, conical, disk, polygonal shapes, and the like (not shown).

The first section 4 can be formed from a freeze-dried and cross-linkedhydrogel that comprises two components, one being polyethylene glycol(“PEG”) and the other component being chitosan. The two polymers, PEGand chitosan may be covalently bonded or blended together to form afreeze dried polymer hydrogel that expands upon contact withphysiological fluids and that has hemostatic properties. Non-covalentbonding may also be used, in several embodiments. Optionally, atransition zone (not shown) may be included where the material of thesecond section 6 can penetrate partially into the distal end 4 b of thefirst section 4, e.g., during fusion, as described further below. Somesuch embodiments enhance the structural stability of the sealant,further enhancing hemostasis.

In several embodiments, the material of the first section 4 may be atleast partially absorbed by the body over time, e.g., over a period ofdays, weeks, or months. Likewise, the material of the second section 6may also be at least partially absorbed by the body over time, e.g.,over a period of days, weeks, or months. Depending on the embodiment,the first section 4 and second section 6 can be made of the samematerial. In some embodiments, the composition of the first section 4and the second section 6 can be adjusted to accommodate their relativeroles in the hemostatic process and the eventual healing of thepuncture. For example, in several embodiments, the rate of absorption ofthe second section 6 can be slower than that of the first section 4,thereby maintaining the sealant over the puncture for a longer period oftime, thus allowing the underlying vessel time to heal. The rate ofdegradation (and thus the specific make-up of the sealant) can beselected based on the size of puncture, rate of blood flow (orinterstitial fluid flow) or blood pressure at the puncture site, or thedegree of mobility that the puncture site will experience (e.g., healingmay take longer at a puncture site that experiences frequent forces frombody motion).

The PEG/chitosan co-polymer sealant can comprise two portions PEG (oneportion PEG-amine and one portion PEG-ester) to one portion chitosan. Inseveral embodiments, the chitosan can be at least partiallydeacetylated. It should be noted that the term “portion”, as usedherein, does not necessary indicate a quantity or ratio of the variouscomponents. Rather, specific details about further aspects of thesealants, including their specific compositions, are discussed below.

Polyethylene Glycol

The PEG used in the sealant can be varied, depending on the embodimentand factors such as the anticipated puncture size, the normal rate ofblood flow in the area of the puncture, the physical status of a patient(e.g., on anti-coagulant medication, etc.). In several embodiments, thePEG-amine portion may be a polymer such as 8A20K-NH2 (e.g., 8-arm 20kilodalton (kDa) molecular weight, with amine terminated arms). Inseveral embodiments, the PEG-ester portion may be a polymer such as4A10K-CM-HBA-NHS (e.g., 4-arm, 10 kDa molecular weight, withcarboxymethyl-hydroxybutyrate-N-hydroxysuccinimidyl functional groups onthe arms). In another embodiment the PEG-ester portion may be a polymersuch as 4A 10K-SS-NHS (e.g., 4-arm, 10 kDa molecular weight withsuccinimidyl succinate functional groups on the arms) or a polymer suchas 4A10K-SG-NHS (e.g., 4-arm, 10 kDa molecular weight with succinimidylglutarate functional groups on the arms) or a mixture of these polymers.

In various embodiments, different precursors may be used to manufactureboth the first section 4 and the second section 6 of the sealant. Forexample, the precursors may comprise polyethylene glycol derivatives orpolyethylene glycols with at least two end groups (e.g., 2 arms) andhaving at least one cross-linkable end group. The first functional groupmay chemically react with the second functional group in-situ to formcovalent bonds and thereby form a cross-linkable gel. In someembodiments, the first functional group or second functional group cancomprise strong electrophiles. For example, the first and/or secondfunctional group may be one or more of epoxide, succinimide,N-hydroxysuccinimide, acrylate, methacrylate, maleimide, andN-hydroxysulfosuccinimide. Additionally, in some embodiments, the firstand/or second functional group may be an amine group, a sulfhydrylgroup, a carboxyl group, and/or a hydroxyl group.

Depending on the embodiments, PEGs of various molecular weights may beused. As discussed above, the determination of molecular weight can bemade based on the desired structural integrity that the sealant willneed to possess, the rate of blood or fluid flow at the puncture site,the disappearance time and other clinical variables. In severalembodiments, the molecular weight of the polyethylene glycols may rangefrom about 2500 Daltons to about 50,000 Daltons. This includespolyethylene glycols with molecular weights ranging from about 2500Daltons to about 5000 Daltons, about 5000 Daltons to about 10,000Daltons, about 10,000 Daltons to about 15,000 Daltons, about 15,000Daltons to about 20,000 Daltons, about 20,000 Daltons to about 25,000Daltons, about 25,000 Daltons to about 30,000 Daltons, about 30,000Daltons to about 35,000 Daltons, about 35,000 Daltons to about 40,000Daltons, about 40,000 Daltons to about 45,000 Daltons, about 45,000Daltons to about 50,000 Daltons, and any molecular weight between thoselisted.

Depending on the embodiments, the polyethylene glycols may have a variednumber of functional groups. For example, in several embodiments, thepolyethylene glycols may include two to eight functional groups,including three, four, five, six, or seven functional groups. Mixturesof polyethylene glycols with varied numbers of functional groups arealso used in some embodiments.

Various derivatives of polyethylene glycol can also be used, dependingon the embodiment. Non-limiting examples of the polyethylene glycolderivatives that may be used include, but are not limited to, branchedpolyethylene glycol derivatives, heterofunctional polyethylene glycolderivatives, linear monofunctional polyethylene glycol derivatives, andeven combinations thereof. Non-limiting examples of branchedpolyethylene glycol derivatives include, but are not limited to, Y-ShapePEG NHS ester (molecular weight of ˜40000 Da), Y-Shape PEG maleimide(molecular weight of ˜40000 Da), Y-Shape PEG acetaldehyde (molecularweight of ˜40000 Da), Y-Shape PEG propionaldehyde (molecular weight of˜40000 Da). Non-limiting examples of heterofunctional polyethyleneglycol derivatives include, but are not limited to, hydroxyl PEGcarboxyl (molecular weight of ˜3500 Da), hydroxyl PEG amine, HCl Salt(molecular weight of ˜3500 Da), amine PEG carboxyl, HCl Salt, (molecularweight of ˜3500 Da), acrylate PEG NHS ester (molecular weight of ˜3500Da), maleimide PEG amine, TFA Salt (molecular weight of ˜3500 Da),maleimide PEG NHS ester (molecular weight of ˜3500 Da), 4-arm PEGsuccinimidyl succinate (pentaerythritol) (molecular weight of ˜10000Da), 8-arms PEG amine (molecular weight of ˜10000-˜20000 Da).Non-limiting examples of linear monofunctional polyethylene glycolderivatives include, but are not limited to methoxy PEG succinimidylcarboxymethyl ester, (molecular weight of ˜10000-˜20000 Da), methoxy PEGmaleimide (molecular weight of ˜10000-˜20000 Da), methoxy PEGvinylsulfone (molecular weight of ˜10000-˜20000 Da), methoxy PEG thiol(molecular weight of ˜10000-−20000 Da), methoxy PEG propionaldehyde(molecular weight of ˜10000-˜20000 Da), methoxy PEG amine, HCl Salt(molecular weight of ˜10000-˜20000 Da).

Chitosan

As discussed above, the copolymer sealant can comprise one portionchitosan. In several embodiments, the chitosan can be at least partiallydeacetylated. In one embodiment, the chitosan can be at least about 50%deacetylated. Chitosan that has a degree of deacetylation between about60% and about 99% is used in several embodiments, including chitosanhaving a degree of deacetylation between about 60% and about 65%,between about 65% and about 70%, between about 70% and about 75%,between about 75% and about 80%, between about 80% and about 85%,between about 85% and about 90%, between about 90% and about 95%,between about 95% and about 96%, between about 96% and about 97%,between about 97% and about 98%, between about 98% and about 99%, andany degree of deacetylation between those values.

As with the PEG components, the chitosan can have a varied molecularweight, depending on the embodiment. While chitosan can have a variedmolecular weight based on its production method, several embodiments ofthe sealant comprise chitosan having molecular weights between about 10kilodaltons (kDa) and about 600 kDa. For example, in severalembodiments, the chitosan component has a molecular weight of betweenabout 10 kDa and about 50 kDa, between about 50 kDa and about 100 kDa,between about 100 kDa and about 150 kDa, between about 150 kDa and about200 kDa, between about 200 kDa and about 250 kDa, between about 250 kDaand about 300 kDa, between about 300 kDa and about 350 kDa, betweenabout 350 kDa and about 400 kDa, between about 400 kDa and about 500kDa, between about 500 kDa and about 600 kDa, and any molecular weightbetween these ranges.

In one embodiment, the chitosan component comprises a chitosan having amolecular weight between 150 kDa and 400 kDa and a degree ofdeacetylation of at least 90%.

In another embodiment, the chitosan component comprises a chitosanhaving a molecular weight between 150 kDa and 400 kDa and a degree ofdeacetylation between 75% and 90%.

The chitosan precursors can optionally be in the free amine form or,alternatively in a salt form of chitosan. Suitable salts include, butare not limited to chitosan chloride, chitosan glutamate, chitosanacetate or other salt forms of chitosan. Mixtures of various saltsand/or salts with the free amine form of chitosan may also be used.

PEG-Chitosan Ratios

As discussed above, in several embodiments, the sealant can comprise twoportions PEG (e.g., PEG amine and PEG ester) and one portion chitosan.The molar ratio of the components can be varied, depending on thedesired properties of the sealant (e.g., time to hemostasis, etc.).Depending on the embodiment, chitosan may be present in a molar ratio ofchitosan to PEG of about 0.0001 to about 1.0. For example, the chitosanmay be present in a molar ratio of chitosan to PEG of from about 0.0001to about 0.0005, from about 0.0005 to about 0.001, from about 0.001 toabout 0.005, from about 0.005 to about 0.01, from about 0.01 to about0.05, from about 0.05 to about 0.1, from about 0.1 to about 0.2, fromabout 0.2 to about 0.3, from about 0.3 to about 0.4, from about 0.4 toabout 0.5, from about 0.5 to about 0.6, from about 0.6 to about 0.7,from about 0.7 to about 0.8, from about 0.8 to about 0.9, from about 0.9to about 1, or any ratios there between (and including endpoints).

Depending on the embodiment, the chitosan may also be present in thesealant composition based on a percentage of the sealant formulation(weight/weight, weight per volume, or volume/volume). For example, thechitosan may be present in a weight percentage in the entire formulationfrom about 0.1% to about 30%, such as about 0.1%, about 1%, about 3%,about 4%, about 5%, about 6%, about 10%, about 15%, about 20%, about25%, or about 30% (or percentages between those listed). In severalembodiments, the chitosan can be present in an amount from about 0.1% toabout 30%, about 0.5% to about 25%, about 0.5% to about 15%, about 0.5%to about 10%, about 0.5% to about 8%, about 0.5% to about 6%, about 0.5%to about 4%, about 2% to about 4%, or any amount there between. Inanother embodiment, the first section comprises between about 4% andabout 6% (by weight) chitosan. Greater or lesser amounts of chitosan canalso be used. In still additional embodiments, the weight ratio ofchitosan in the final hydrogel formulation is between about 1% and about6% by weight of chitosan, including about 1% to about 2%, about 20% toabout 3%, about 30% to about 4%, about 4% to about 5%, about 5% to about6%, and percentages in between those listed (and including endpoints).

Depending on the embodiment, PEG-amine may be present in a molar ratioof PEG-amine to PEG-ester and chitosan of about 0.09 to about 9.9. Forexample, the PEG-amine may be present in a molar ratio of PEG-amine tothe PEG-ester and chitosan of about 0.09 to about 0.1, about 0.1 toabout 0.2, of about 0.2 to about 0.3, of about 0.3 to about 0.4, ofabout 0.4 to about 0.5, of about 0.5 to about 0.6, of about 0.6 to about0.7, of about 0.7 to about 0.8, of about 0.8 to about 0.9, about 0.9 toabout 1.0, about 1.0 to about 2.0, about 2.0 to about 3.0, about 3.0 toabout 4.0, about 4.0 to about 5.0, about 5.0 to about 6.0, about 6.0 toabout 7.0, about 7.0 to about 8.0, about 8.0 to about 9.0, about 9.0 toabout 9.9, or any amount there between (and including endpoints).

Alternatively, PEG-amine may be present in the sealant composition basedon a percentage of the sealant formulation (weight/weight, weight pervolume, or volume/volume). For example, the PEG-amine may be present ina weight percentage in the entire formulation from about 99.0% to about1.0%, about 90.0% to about 10.0%, about 80.0% to about 20.0%, about70.0% to about 30.0%, about 60.0% to about 40.0%, about 55.0% to about45.0%, about 53.0% to about 47.0%, about 52.0% to about 48.0%, about50.0% to about 48.0%, and any percentage between or including thoseamounts.

Depending on the embodiment, PEG-ester may be present in a molar ratioof PEG-ester to PEG-amine and chitosan of about 0.09 to 19.9. Forexample, the PEG-ester may be present in a molar ratio of PEG-ester toPEG-amine and chitosan of about 0.09 to about 0.1, about 0.1 to about0.2, of about 0.2 to about 0.3, of about 0.3 to about 0.4, of about 0.4to about 0.5, of about 0.5 to about 0.6, of about 0.6 to about 0.7, ofabout 0.7 to about 0.8, of about 0.8 to about 0.9, about 0.9 to about1.0, about 1.0 to about 2.0, about 2.0 to about 3.0, about 3.0 to about4.0, about 4.0 to about 5.0, about 5.0 to about 6.0, about 6.0 to about7.0, about 7.0 to about 8.0, about 8.0 to about 9.0, about 10 to about11, about 11 to about 12, about 12 to about 13, about 13 to about 14,about 14 to about 15, about 15 to about 16, about 16 to about 17, about17 to about 18, about 18 to about 19, 19 to about 19.9, or any amountthere between.

Depending on the embodiment, PEG-ester may be present in the sealantcomposition based on a percentage of the sealant formulation(weight/weight, weight per volume, or volume/volume). For example, thePEG-ester may be present in a weight percentage in the entireformulation from about 99.0% to about 1.0%, about 90.0% to about 10.0%,about 80.0° % to about 20.0%, about 70.0% to about 30.0%, about 60.0% toabout 40.0%, about 55.0% to about 45.0%, about 53.0% to about 47.0%,about 52.0% to about 48.0%, about 52.0% to about 50.0%, and anypercentage between or including those amounts.

In several embodiments, the molar ratio of chitosan to PEG-ester isbetween approximately 0.0001 to about 1. In another embodiment, themolar ratio of chitosan to PEG-ester is between approximately 0.0001 toabout 0.005. In yet another embodiment the molar ratio of chitosan toPEG-ester is between approximately 0.005 to about 0.01. In severalembodiments the equivalent ratio of active group sites of chitosan tothe active group sites of PEG-ester is between approximately 0.01 toabout 9. In another embodiment the equivalent ratio of active groupsites of chitosan to the active group sites of PEG-ester is betweenapproximately 0.01 to about 2. In another embodiment the equivalentratio of active group sites of chitosan to the active group sites ofPEG-ester is between approximately 0.1 to about 2. In another embodimentthe equivalent ratio of active group sites of chitosan to the activegroup sites of PEG-ester is between approximately 0.5 to about 1.5.

As discussed above, in several embodiments a second section may bepresent and may consist essentially of the non-cross-linked precursors.In several embodiments, the second section can be formed from a solidmass of non-freeze-dried, non-cross-linked hydrogel precursors, theprecursors remaining in an unreactive state until exposed to an aqueousphysiological environment, whereupon the precursors undergo in-situcrosslinking with one another to provide an improved adhesion of thesealant to the arteriotomy. The hydrogel precursors may comprisepolyethylene glycol with ester end groups, polyethylene glycol withamine end groups that are fused or otherwise attached onto the distalend of the sealant. Chitosan with various degrees of deacetylation mayor may not be present in the second section. Chitosan's weightpercentage in the second section may vary from 0.1% to 80%, if present.In another embodiment chitosan is present in the second section in aweight percentage between 1% and 30%. In yet another embodiment chitosanis present in the second section in a weight percentage between 10% and300%. In an additional embodiment, chitosan fibers, chitosan mesh orchitosan particles may be incorporated or fused together with thenon-cross-linked hydrogel precursors. For example, the solid mass may beformed as a substantially uniform solid plug or may be formed as asintered mass of powder and fibers or mesh. The chitosan fibers, mesh orparticles may act as a reinforcement element to increase the integrityof the cross-linked network. The melted precursors, which may or may notcomprise chitosan fibers, chitosan mesh or chitosan particles may beapplied to the distal end of the tubular roll within the tubular member,and allowed to solidify to create the solid mass fused to the distal endof the tubular roll.

While several embodiments relate to the use of chitosan-containingcopolymers, the chitosan may also be used independently as a sealant toreduce the time to hemostasis. In such embodiments, the chitosan rangesfrom about 0.01% of the sealant to about 99.9% of the sealant.

Additional Agents

In additional embodiments, one or more additional compositions can beadded to the co-polymer sealant. In several embodiments, the additionalagents are added to the sealant to facilitate sealing of the puncture.In several embodiments, pro-thrombotic agents may be included in thesealant. For example, biological pro-thrombotics are included, inseveral embodiments. These include, but are not limited to, one or moreof collagen, fibrin, fibrinogen, thrombin, Factor VIII, Factor IX,Factor X, calcium salts, carboxymethylcellulose, oxidized cellulose,alginates, gelatin, or other protein-based material. Synthetic materialsthat facilitate thrombosis may include polyglycolic acids (PGA's),polylactides (PLA's), polyvinyl alcohol (PVA), and the like.

In several embodiments, the first section 4 (and/or second section 6)may further include therapeutic and/or pharmaceutical agents, e.g., topromote healing, prevent infection and/or other adverse medical events,and the like.

For example, in several embodiments, the sealant may further compriseone or more drugs provided below, either alone or in combination. Thedrugs utilized may also be the equivalent of, derivatives of, or analogsof one or more of the drugs provided below. The drugs may include butare not limited to pharmaceutical agents including antimicrobial agents(e.g., antibiotic, antiviral, antiparasitic, antifungal agents),anti-inflammatory agents (including steroids or non-steroidalanti-inflammatory), biological agents including hormones, enzymes orenzyme-related components, antibodies or antibody-related components,oligonucleotides (including DNA, RNA, short-interfering RNA, antisenseoligonucleotides, and the like), DNA/RNA vectors, viruses (either wildtype or genetically modified) or viral vectors, peptides, proteins,enzymes, extracellular matrix components, and live cells configured toproduce one or more biological components. The use of any particulardrug is not limited to its primary effect or regulatory body-approvedtreatment indication or manner of use. Drugs also include compounds orother materials that reduce or treat one or more side effects of anotherdrug or therapeutic agent. As many drugs have more than a single mode ofaction, the listing of any particular drug within any one therapeuticclass below is only representative of one possible use of the drug andis not intended to limit the scope of its use with the ophthalmicimplant system.

As discussed above, the therapeutic agents that are included in thesealant may be combined with any number of excipients as is known in theart. Excipients that are suitable for use include, but are not limitedto, biodegradable polymeric excipients, benzyl alcohol, ethylcellulose,methylcellulose, hydroxymethylcellulose, cetyl alcohol, croscarmellosesodium, dextrans, dextrose, fructose, gelatin, glycerin, monoglycerides,diglycerides, kaolin, calcium chloride, lactose, lactose monohydrate,maltodextrins, polysorbates, pregelatinized starch, calcium stearate,magnesium stearate, silicon dioxide, cornstarch, talc, and the like. Theone or more excipients may be included in total amounts as low as about1%, 5%, or 10% and in other embodiments may be included in total amountsas high as about 50%, 70% or 90%.

Examples of drugs that may be used in the sealant may include variousanti-secretory agents; antimitotics and other anti-proliferative agents,adrenergic antagonists, including for example, beta-blocker agents suchas atenolol propranolol, metipranolol, betaxolol, carteolol,levobetaxolol, levobunolol and timolol; adrenergic agonists orsympathomimetic agents such as epinephrine, dipivefrin, clonidine,aparclonidine, and brimonidine; parasympathomimetics or cholingericagonists such as pilocarpine, carbachol, phospholine iodine, andphysostigmine, salicylate, acetylcholine chloride, eserine, diisopropylfluorophosphate, demecarium bromide); muscarinics; carbonic anhydraseinhibitor agents, including topical and/or systemic agents, for exampleacetozolamide, brinzolamide, dorzolamide and methazolamide,ethoxzolamide, diamox, and dichlorphenamide; mydriatic-cycloplegicagents such as atropine, cyclopentolate, succinylcholine, homatropine,phenylephrine, scopolamine and tropicamide; prostaglandins such asprostaglandin F2 alpha, antiprostaglandins, prostaglandin precursors, orprostaglandin analog agents such as bimatoprost, latanoprost, travoprostand unoprostone.

Other examples of drugs that may be included in the sealant may alsoinclude anti-inflammatory agents including for example glucocorticoidsand corticosteroids such as betamethasone, cortisone, dexamethasone,dexamethasone 21-phosphate, methylprednisolone, prednisolone21-phosphate, prednisolone acetate, prednisolone, fluroometholone,loteprednol, medrysone, fluocinolone acetonide, triamcinolone acetonide,triamcinolone, triamcinolone acetonide, beclomethasone, budesonide,flunisolide, fluorometholone, fluticasone, hydrocortisone,hydrocortisone acetate, loteprednol, rimexolone and non-steroidalanti-inflammatory agents including, for example, diclofenac,flurbiprofen, ibuprofen, bromfenac, nepafenac, and ketorolac,salicylate, indomethacin, ibuprofen, naxopren, piroxicam and nabumetone;anti-infective or antimicrobial agents such as antibiotics including,for example, tetracycline, chlortetracycline, bacitracin, neomycin,polymyxin, gramicidin, cephalexin, oxytetracycline, chloramphenicol,rifampicin, ciprofloxacin, tobramycin, gentamycin, erythromycin,penicillin, sulfonamides, sulfadiazine, sulfacetamide, sulfamethizole,sulfisoxazole, nitrofurazone, sodium propionate, aminoglycosides such asgentamicin and tobramycin; fluoroquinolones such as ciprofloxacin,gatifloxacin, levofloxacin, moxifloxacin, norfloxacin, ofloxacin;bacitracin, erythromycin, fusidic acid, neomycin, polymyxin B,gramicidin, trimethoprim and sulfacetamide; antifungals such asamphotericin B and miconazole; antivirals such as idoxuridinetrifluorothymidine, acyclovir, gancyclovir, interferon; antimicotics;immune-modulating agents such as antiallergenics, including, forexample, sodium chromoglycate, antazoline, methapyriline,chlorpheniramine, cetrizine, pyrilamine, prophenpyridamine;anti-histamine agents such as azelastine, emedastine and levocabastine;immunological drugs (such as vaccines and immune stimulants); MAST cellstabilizer agents such as cromolyn sodium, ketotifen, lodoxamide,nedocrimil, olopatadine and pemirolastciliary body ablative agents, suchas gentimicin and cidofovir; and other ophthalmic agents such asverteporfin, proparacaine, tetracaine, cyclosporine and pilocarpine;inhibitors of cell-surface glycoprotein receptors; decongestants such asphenylephrine, naphazoline, tetrahydrazoline; lipids or hypotensivelipids; dopaminergic agonists and/or antagonists such as quinpirole,fenoldopam, and ibopamine; vasospasm inhibitors; vasodilators;antihypertensive agents; angiotensin converting enzyme (ACE) inhibitors;angiotensin-1 receptor antagonists such as olmesartan; microtubuleinhibitors; molecular motor (dynein and/or kinesin) inhibitors; actincytoskeleton regulatory agents such as cyctchalasin, latrunculin,swinholide A, ethacrynic acid, H-7, and Rho-kinase (ROCK) inhibitors;remodeling inhibitors; modulators of the extracellular matrix such astert-butylhydro-quinolone and AL-3037A; adenosine receptor agonistsand/or antagonists such as N-6-cylclophexyladenosine and(R)-phenylisopropyladenosine; serotonin agonists; hormonal agents suchas estrogens, estradiol, progestational hormones, progesterone, insulin,calcitonin, parathyroid hormone, peptide and vasopressin hypothalamusreleasing factor; growth factor antagonists or growth factors,including, for example, epidermal growth factor, fibroblast growthfactor, platelet derived growth factor or antagonists thereof,transforming growth factor beta, somatotrapin, fibronectin, connectivetissue growth factor, bone morphogenic proteins (BMPs); cytokines suchas interleukins, CD44, cochlin, and serum amyloids, such as serumamyloid A.

Other therapeutic agents may include neuroprotective agents such aslubezole, nimodipine and related compounds, and including blood flowenhancers such as dorzolamide or betaxolol; compounds that promote bloodoxygenation such as erythropoeitin; sodium channels blockers; calciumchannel blockers such as nilvadipine or lomerizine; glutamate inhibitorssuch as memantine nitromemantine, riluzole, dextromethorphan oragmatine; acetylcholinsterase inhibitors such as galantamine;hydroxylamines or derivatives thereof, such as the water solublehydroxylamine derivative OT-440; synaptic modulators such as hydrogensulfide compounds containing flavonoid glycosides and/or terpenoids,such as ginkgo biloba; neurotrophic factors such as glial cell-linederived neutrophic factor, brain derived neurotrophic factor; cytokinesof the IL-6 family of proteins such as ciliary neurotrophic factor orleukemia inhibitory factor; compounds or factors that affect nitricoxide levels, such as nitric oxide, nitroglycerin, or nitric oxidesynthase inhibitors; cannabinoid receptor agonsists such as WIN55-212-2;free radical scavengers such as methoxypolyethylene glycol thioester(MPDTE) or methoxypolyethlene glycol thiol coupled with EDTA methyltriester (MPSEDE); anti-oxidants such as astaxathin, dithiolethione,vitamin E, or metallocorroles (e.g., iron, manganese or galliumcorroles); compounds or factors involved in oxygen homeostasis such asneuroglobin or cytoglobin; inhibitors or factors that impactmitochondrial division or fission, such as Mdivi-1 (a selectiveinhibitor of dynamin related protein 1 (Drp1)); kinase inhibitors ormodulators such as the Rho-kinase inhibitor H-1152 or the tyrosinekinase inhibitor AG1478; compounds or factors that affect integrinfunction, such as the Beta 1-integrin activating antibody HUTS-21;N-acyl-ethanaolamines and their precursors, N-acyl-ethanolaminephospholipids; stimulators of glucagon-like peptide 1 receptors (e.g.,glucagon-like peptide 1); polyphenol containing compounds such asresveratrol; chelating compounds; apoptosis-related protease inhibitors;compounds that reduce new protein synthesis; radio-therapeutic agents;photodynamic therapy agents; gene therapy agents; genetic modulators;auto-immune modulators that prevent damage to nerves or portions ofnerves (e.g., demyelination) such as glatimir; myelin inhibitors such asanti-NgR Blocking Protein, NgR(310)ecto-Fc; other immune modulators suchas FK506 binding proteins (e.g., FKBP51).

Other therapeutic agents that may be used include: other beta-blockeragents such as acebutolol, atenolol, bisoprolol, carvedilol, asmolol,labetalol, nadolol, penbutolol, and pindolol; other corticosteroidal andnon-steroidal anti-inflammatory agents such aspirin, betamethasone,cortisone, diflunisal, etodolac, fenoprofen, fludrocortisone,flurbiprofen, hydrocortisone, ibuprofen, indomethacine, ketoprofen,meclofenamate, mefenamic acid, meloxicam, methylprednisolone,nabumetone, naproxen, oxaprozin, prednisolone, prioxicam, salsalate,sulindac and tolmetin; COX-2 inhibitors like celecoxib, rofecoxib and.Valdecoxib; other immune-modulating agents such as aldesleukin,adalimumab (HUMIRA®), azathioprine, basiliximab, daclizumab, etanercept(ENBREL®), hydroxychloroquine, infliximab (REMICADE®), leflunomide,methotrexate, mycophenolate mofetil, and sulfasalazine; otheranti-histamine agents such as loratadine, desloratadine, cetirizine,diphenhydramine, chlorpheniramine, dexchlorpheniramine, clemastine,cyproheptadine, fexofenadine, hydroxyzine and promethazine; otheranti-infective agents such as aminoglycosides such as amikacin andstreptomycin; anti-fungal agents such as amphotericin B, caspofungin,clotrimazole, fluconazole, itraconazole, ketoconazole, voriconazole,terbinafine and nystatin; anti-malarial agents such as chloroquine,atovaquone, mefloquine, primaquine, quinidine and quinine;anti-mycobacterium agents such as ethambutol, isoniazid, pyrazinamide,rifampin and rifabutin; anti-parasitic agents such as albendazole,mebendazole, thiobendazole, metronidazole, pyrantel, atovaquone,iodoquinaol, ivermectin, paromycin, praziquantel, and trimatrexate;other anti-viral agents, including anti-CMV or anti-herpetic agents suchas acyclovir, cidofovir, famciclovir, gangciclovir, valacyclovir,valganciclovir, vidarabine, trifluridine and foscarnet; proteaseinhibitors such as ritonavir, saquinavir, lopinavir, indinavir,atazanavir, amprenavir and nelfinavir;nucleotide/nucleoside/non-nucleoside reverse transcriptase inhibitorssuch as abacavir, ddI, 3TC, d4T, ddC, tenofovir and emtricitabine,delavirdine, efavirenz and nevirapine; other anti-viral agents such asinterferons, ribavirin and trifluridiene; other anti-bacterial agents,including cabapenems like ertapenem, imipenem and meropenem;cephalosporins such as cefadroxil, cefazolin, cefdinir, cefditoren,cephalexin, cefaclor, cefepime, cefoperazone, cefotaxime, cefotetan,cefoxitin, cefpodoxime, cefprozil, ceftaxidime, ceftibuten, ceftizoxime,ceftriaxone, cefuroxime and loracarbef; other macrolides and ketolidessuch as azithromycin, clarithromycin, dirithromycin and telithromycin;penicillins (with and without clavulanate) including amoxicillin,ampicillin, pivampicillin, dicloxacillin, nafcillin, oxacillin,piperacillin, and ticarcillin; tetracyclines such as doxycycline,minocycline and tetracycline; other anti-bacterials such as aztreonam,chloramphenicol, clindamycin, linezolid, nitrofurantoin and vancomycin;alpha blocker agents such as doxazosin, prazosin and terazosin;calcium-channel blockers such as amlodipine, bepridil, diltiazem,felodipine, isradipine, nicardipine, nifedipine, nisoldipine andverapamil; other anti-hypertensive agents such as clonidine, diazoxide,fenoldopan, hydralazine, minoxidil, nitroprusside, phenoxybenzamine,epoprostenol, tolazoline, treprostinil and nitrate-based agents;prostaglandin PDE-5 inhibitors and other prostaglandin agents such asalprostadil, carboprost, sildenafil, tadalafil and vardenafil;anti-proliferative agents such as sirolimus, tacrolimus, everolimus,zotarolimus, paclitaxel and mycophenolic acid; hormonal-related agentsincluding levothyroxine, fluoxymestrone, methyltestosterone, nandrolone,oxandrolone, testosterone, estradiol, estrone, estropipate, clomiphene,gonadotropins, hydroxyprogesterone, levonorgestrel, medroxyprogesterone,megestrol, mifepristone, norethindrone, oxytocin, progesterone,raloxifene and tamoxifen; anti-neoplastic agents, including alkylatingagents such as carmustine lomustine, melphalan, cisplatin,fluorouracil3, and procarbazine antibiotic-like agents such asbleomycin, daunorubicin, doxorubicin, idarubicin, mitomycin andplicamycin; anti proliferative agents (such as 1,3-cis retinoic acid,5-fluorouracil, taxol, rapamycin, mitomycin C and cisplatin);antimetabolite agents such as cytarabine, fludarabine, hydroxyurea,mercaptopurine and 5-fluorouracil (5-FU); immune modulating agents suchas aldesleukin, imatinib, rituximab and tositumomab; mitotic inhibitorsdocetaxel, etoposide, vinblastine and vincristine; radioactive agentssuch as strontium-89; and other anti-neoplastic agents such asirinotecan, topotecan and mitotane.

Optionally, the second section may further include one or more pHadjusting agents. For example, a pH adjusting agent, e.g., sodiumborate, sodium phosphate, sodium bicarbonate, and/or other salts, suchas Na₂B₄O₇.10H₂O in crystalline or powder form, may be melted with theprecursors (as discussed in more detail below) and then applied with theprecursors to the distal end 4 b of the first section 4. Alternatively,the pH adjusting agent may be applied to the second section 6 afterfusing the melted precursors to the first section 4, e.g., by bonding orimpregnating crystals of borate or other salts to the outer surface ofthe solid mass of non-cross-linked precursors and/or by melting andapplying a coating of melted salts to the outer surface, e.g., similarto embodiments disclosed in the references incorporated by referenceelsewhere herein. In addition or alternatively, one or more pH adjustingagents may be provided on the first section 4, if desired.

In this manner, the pH adjusting agent may alter the localized pH on oraround the sealant 2, e.g., when deployed within a puncture to enhancecross-linking and/or creation of a desired adhesive material.Alternatively, the pH and/or buffering capacity of interstitial bodyfluids and/or blood may be effective to drive or facilitatecross-linking of the second section 6. For example, the precursors ofthe second section 6 may be optimized to take into account all of thesefactors and/or form a robust adherence to tissue.

In additional embodiments, other agents such as diluents, including butnot limited to, low molecular PEG and/or glycerol, may be added to thesealant.

These additional agents may be embedded in the sealant, encased in thesealant (e.g., as a “core”), co-fabricated with the sealant, and/orapplied as one or more coatings or layers. In addition, the material ofthe first section 4 may have a substantially uniform composition or thecomposition may be varied, e.g., along its length and/or withinunderlying layers within the first section 4.

Sealant Fabrication

In several embodiments, the first section 4 may be formed entirely fromfreeze-dried hydrogel, e.g., initially formed as a thin sheet offreeze-dried polymer. For example, to fabricate the first section 4 fromblends of PEG and chitosan, PEG-amine, PEG-ester and chitosan powdersintended to form the hydrogel may be filled into separate vessels (e.g.,vials). Phosphate and borate buffers may be made, e.g., by dissolvingthe sodium borate and sodium phosphate in sterile water for injection(WFI) and adjusting the pH of each solution to meet pre-establishedrequirements. The chitosan used may be in the form of chitosan salt(e.g. chitosan chloride, chitosan glutamate, chitosan acetate or othersalt forms of chitosan). The chitosan salt powder may be mixed (orpre-mixed, depending on the embodiment) with the PEG-ester or PEG-aminepowder in predetermined amounts. The powders may then be dissolved intheir respective buffer solutions, e.g. in one vial the PEG-ester andchitosan in the phosphate buffer solution, and in the other vialPEG-amine in the borate buffer solution. Alternatively, the chitosanpowder can be mixed with the PEG-amine in the borate buffer solution.Still alternatively, the chitosan powder can be mixed and dissolved ineach of the vials, e.g., with both PEG-amine and PEG-ester, and thenlater combined. The molar ratio of the PEG-ester to PEG-amine may besuch that the PEG-ester groups are in excess of PEG-amine so thatPEG-ester groups are available to react with the amine groups of thechitosan polymer chains to create covalent bonding between the PEG andthe chitosan polymer chains. Additional information on the ratio of thevarious PEG precursors is disclosed in more detail above. Theseprecursor solutions may be mixed together, poured into trays, andfreeze-dried. The freeze-dried material may optionally be subjected to aseries of heat and/or humidity conditioning cycles, e.g., to completethe polymerization reaction.

In several embodiments, the freeze-dried and conditioned sheet ofhydrogel sealant may then be trimmed according to size and massrequirements, e.g., cut to a desired length for the finished firstsection 4. For example, as shown in FIG. 1A, the trimmed hydrogel may bedried, rolled, and loaded into a transfer tube 8 for subsequentattachment to the second section 6.

To fabricate the non-freeze-dried, non-cross-linked distal section 6 ofthe sealant 2, PEG-amine and PEG-ester powders (or other cross-linkablepolymer precursors) may be melted in an appropriate vessel (e.g., abeaker or flask), mixed, and heated at a pre-determined temperature andfor a duration sufficient to fully melt and uniformly mix the mixture.One of ordinary skill in the art will appreciate that the melting pointof the various precursors will depend, at least in part on theirmolecular weight. However, one of ordinary skill in the art will readilybe able to, based on the disclosure provided herein, prepare theprecursors appropriately to generate the co-polymer sealants. In anotherembodiment the non-freeze dried section may additionally containchitosan fibers, a chitosan mesh or chitosan particles incorporated inthe melted section. For example, the precursors may be melted in asubstantially dry air or inert gas environment, e.g., a vacuum chamber.This approach can reduce entrapment of moisture, which may otherwisecause premature degradation and crosslinking. Using a vacuum generator,the melted PEG, which may or may not comprise chitosan fibers, chitosanmesh or chitosan particles, may then be applied onto the distal end 4 bof the rolled freeze-dried first section 4.

For example, as described above, the first section 4 may be formed froma rolled sheet and loaded into a transfer tube 8, as shown in FIG. 1A.The transfer tube 8 may have an inner diameter or other cross-sectioncorresponding to the desired outer diameter or cross-section for thefinished sealant 2. The transfer tube 8 may be formed from any materialsufficient to handle the processing parameters of the assembly process,such as polymers, metals, or composite materials, and may optionallyinclude desired coatings, e.g., PTFE to facilitate insertion of thefirst section 4 and/or removal of the sealant 2.

The first section 4 may be loaded into the transfer tube 8 such that thedistal end 4 b of the first section 4 is offset inwardly a predetermineddistance L6 from the end of the transfer tube 8, e.g., corresponding toor greater than the desired length of the second section 6. For example,for a desired finished length of the second section 6 of about 1.5millimeters, the distal end 4 b may be offset inwardly about twomillimeters (2.0 mm) from the end of the transfer tube 8 (with anyexcess material may trimmed off later, as described below). Using thevacuum generator, the melted non-cross-linked PEG, which may or may notcomprise chitosan fibers, chitosan mesh or chitosan particles, is thenapplied onto the distal end 4 b of the rolled freeze-dried sealant,e.g., the vacuum directing the melted PEG into the transfer tube 8 andagainst the distal end 4 b of the first section 4 (as represented by thearrow labeled “vacuum”). Thus, the transfer tube 8 may mold the meltedPEG into the desired shape, e.g., diameter and/or length, for the secondsection 6.

The vacuum may cause the melted precursors to nominally abut the distalend 4 b of the first section 4, and/or may partially draw the meltedprecursors into the pores and/or other open spaces within the firstsection 4, e.g., due to capillary action and the like. In thissituation, a transition zone 7 may be created within the distal end 4 bof the first section 4 in which the melted precursors permeate thefreeze-dried hydrogel or other material of the first section 4, whichmay enhance fusing the second section 6 to the first section 4. Forexample, the melted precursors may quickly cool under ambient conditionssuch that the penetration into the distal end 4 b may be relativelyshort, e.g., resulting in a transition zone 7 of less than a fewmillimeters (mm) (e.g., less than about five mm, less than about 4 mm,less than about 3 mm, less than about 2 mm, less than about onemillimeter, or less).

The melted precursors may be dried under ambient conditions, e.g.,simply allowed to cool and solidify, or alternatively, the melted andapplied precursors may be exposed to desired conditions to accelerate orfacilitate solidification of the melted precursors. The vacuum processeffectively fuses the two sections together to provide a length ofsealant 2.

Chitosan fibers may be manufactured by the technique of fiber spinningfrom solutions of chitosan in volatile solvents (e.g., electrospinning).A chitosan mesh may be manufactured by freeze drying a solution of highconcentration of chitosan. Alternatively chitosan may be cross-linked bya variety of cross-linkers to create highly cross-linked chitosanpolymer chains which may further be processed to manufacture chitosanfibers or a mesh. While in some embodiments, chemical cross-linkingagents can be used (e.g., gluteraldehdye, formaldehyde), in severalembodiments, natural cross-linkers such as genipin are used.Electrospinning methods can also be used to manufacture cross-linkedchitosan fibers (e.g., fibrous mats or meshes). Vapor cross-linking mayalso be used, in several embodiments.

As discussed above, various ratios of PEG and chitosan can be used toprovide a final freeze dried hydrogel that has high swelling capacityupon contact with physiological fluids as well as hemostatic properties.In several embodiments, two PEG precursors are combined with chitosan.In certain such embodiments, one PEG precursor contains ester end groupsand one contains amine end groups. The PEG precursors can react withchitosan (the PEG ester can react with the amine groups of chitosan) andwith each other (PEG-ester reacts with PEG-amine) and can provide apartially cross-linked network that upon freeze drying can result in ahighly porous hydrogel material.

The ratio of PEG-ester to PEG-amine precursors as well as the ratio ofthe PEG precursors to the chitosan can alter final properties of thefreeze dried hydrogel. As discussed above, the weight ratio of chitosanin the final hydrogel formulation can be between about 0.1 and about 30%wt, though in several embodiments, the weight ratio of chitosan in thefinal hydrogel formulation is between about 1% and about 10%. In oneembodiment, the first section comprises between about 2% and about 4%(by weight) chitosan. In still additional embodiments, the final freezedried hydrogel contains between about 4% and about 6% by weight ofchitosan. The ratio of the PEG precursor that has ester active groupswith regards to the PEG precursor that has amine end groups can impactthe crosslinking density, porosity and integrity of the freeze driedpolymer network. In some embodiments, the PEG-ester is in excess of thePEG-amine in order for some ester groups to be able to covalently reactwith the amine groups of the chitosan. These resulting hydrogels containchitosan within their polymer network where chitosan is covalentlybonded to the PEG components. This method increases the swellingcapacity of the final freeze dried hydrogel material as well as thehemostatic ability by increasing the total surface area of the hydrogelmaterial.

As shown in FIG. 2A, a chitosan bioabsorbable mesh 6 a′ may be embeddedwithin and/or surround the precursors 6 b′ of a second section 6′. Themesh 6 a′ of bioabsorbable chitosan may have greater rigidity,elasticity, and/or other desired properties than the solidifiedprecursors 6 b.′ In addition, as shown, the mesh 6 a′ may include one ormore fibers or filaments having a helical configuration (one helicalfilament shown), or alternatively the mesh 6 a′ may include a braid offilaments, a rolled porous mat, and the like (not shown). In oneembodiment, the mesh 6 a′ may be embedded in the precursors 6 b′ of thesecond section 6,′ e.g., by inserting the reinforcement element(s) intothe end of the transfer tube 8 (not shown, see FIG. 1A) before applyingthe melted precursors (not shown), as described above. Thus, as theapplied precursors are drawn into the transfer tube 8 and cool (or areotherwise dried and/or solidified), the precursors 6 b′ may permeatethrough and/or surround the mesh 6 a,′ thereby embedding the element(s)in the second section 6.′

As shown in FIG. 2B, chitosan reinforcing particles or fillers 6 a″ maybe provided in a second section 6″. For example, compositions ofchitosan may be mixed into the melted precursor mixture, and then thereinforcing fillers 6 a″ may be applied to the distal end 4 b of thefirst section 4 (not shown) along with the precursors 6 b,″ e.g., usingthe vacuum process described above. Thus, the filler material 6 a″ maybe distributed randomly, substantially uniformly, or in a desiredpattern throughout the second section 6,″ thereby enhancing therigidity, reducing the brittleness, and/or otherwise modifying theproperties of the precursors 6 b″ of the second section 6″ in a desiredmanner.

As discussed above, diluents may be included in the formulation in someembodiments. In some such embodiments, the diluents are added to theformulation, (e.g., the melted precursors) before application to thefirst section 4, so as to improve the mechanical strength and/orintegrity of the first section 6 and/or to minimize the brittleness ofthe second section 6.

It will be appreciated that the shape of any of the sealants herein maybe modified to have a shape that is conducive to controlled deformation.Examples include an inverted golf tee, an hourglass, swept or wavysurfaces, tubular or solid rod cross-sections or shapes, elliptical,triangular, square, conical, disk, polygonal shapes, and the like (notshown).

As shown in FIG. 1, the first section 4 and the second section 6 (oralternatively section 6, if no first section 4 is included) may includea lumen 5 extending between the proximal and distal ends 4 a, 4 b of thefirst section 4 and through the second section 6, e.g., to facilitatedelivery of the sealant 2. For example, the lumen 5 may be dimensionedto accommodate receiving a balloon catheter or other positioning membertherethrough, e.g., such that the sealant 2 may slide relative to orpass over the positioning member and/or the positioning member may bedirected axially relative to the sealant. Alternatively, the sealant 2may be a substantially continuous rod of material, e.g., such that thesealant 2 may be delivered into a puncture using a cartridge or shuttlewithout a positioning member.

In addition (or alternatively), if the sealant 2 includes a lumen 5, thelumen 5 may be created when the first section 4 is formed, e.g., if thefirst section 4 is rolled from one or more sheets or layers of materialor formed by molding. Alternatively, the lumen 5 may be formed by boringinto or otherwise removing material from an already formed and solidfirst section 4, second section 6, or through the entire sealant 2. Forexample, if the first section 4 is formed from a rolled sheet, a rod orother mandrel 9 (which may be fabricated similar to the transfer tube 8)may be inserted through the lumen 5 before the second section 6 isapplied to the distal end 4 b, e.g., that extends from the transfer tube8, as shown in FIG. 1A. Thus, the second section 6 may be molded andfused to distal end 4 b around the mandrel 9, e.g., within the transfertube 8. The mandrel 8 may be removed once the melted precursors havesolidified, resulting in a continuous lumen through the second section 6and the first section 4. Alternatively, the portion of the lumen 5through the second section 6 may be bored, drilled, or otherwise createdafter the second section 6 is formed and fused to the first section 5.

The dimensions of the sealant can be tailored to the specificapplication (e.g., larger width and/or longer to seal larger punctures,or smaller/shorter for smaller punctures). In several embodiments, thesealant 2 has an overall length between about three and twentymillimeters (3-20 mm), including between about 3 and about 5 mm, betweenabout 5 and about 7 mm, between about 7 and about 9 mm, between about 9and about 11 mm, between about 11 and about 13 mm, between about 13 andabout 15 mm, between about 15 and about 15.5 mm, between about 15.5 andabout 16 mm, between about 16 and about 16.5 mm, between about 16.5 andabout 17 mm, between about 17 and about 20 mm, or any lengththerebetween. Shorter or longer sealants may also be used, as is neededfor specific sealing applications.

The second portion 6 of the sealant can be any percentage of the totallength of the sealant. For example, while the non-limiting embodimentshown in FIG. 1 depicts a sealant with the first section 4 beingsubstantially longer than the second section 6, it will be appreciatedthat, alternatively, the sections 4, 6 may have similar lengths, or thesecond section 6 may be longer than the first section 4. In a furtheralternative embodiment, the first section 4 may be omitted, and thesecond section 6 may provide the entire length of the sealant 2 (notshown), e.g., having a length between about three and twenty millimeters(3-20 mm).

For example, the first section 4 may have a length between about zero(if the sealant 2 is formed entirely from the second section 6) andtwenty millimeters (0-20 mm), e.g., between about five and twentymillimeters (5-20 mm), e.g., about fifteen millimeters (15 mm). Thesecond section 6 may have an outer diameter similar to the first section4, but may have a length that is substantially shorter, e.g., betweenabout zero (if the sealant 2 is formed entirely from the first section4) and eight millimeters (0-8 mm), e.g., between about half and fivemillimeters (0.5-5.0 mm), e.g., about 1.5 millimeters.

Depending on the application the, outer diameter (or othercross-sectional dimension) of the sealant is between about one and abouteight millimeters, including between about 1 mm to about 3 mm, about 3mm to about 5 mm, about 5 to about 8 mm, and any diameter or dimensionbetween those listed. For example, in several embodiments, the lateraldimension of the sealant is between about 1 and about 3 mm, includingbetween about 1 mm and about 1.25 mm, between about 1.25 mm and about1.5 mm, between about 1.5 mm and about 1.75 mm, between about 1.75 mmand about 2 mm, between about 2 mm and about 2.5 mm, between about 2.5mm and about 3 mm, and any dimension between those listed. Sealants withlarger or smaller lateral dimensions may also be used.

Devices for Sealant Deployment

Turning to FIGS. 3A-3D, an apparatus 710 is shown that generallyincludes a positioning member 714 and a cartridge 716 carried on thepositioning member 714 for delivering a sealant 2 therein into apuncture (not shown). The cartridge 716 can include a sealant sleeve 750carrying sealant 2 therein (which can include any of the sealantfeatures described herein), and surrounding a distal end 734 of asupport member 730 adjacent the sealant 2, and a handle or hub 723 onthe proximal end 732 of the support member 730. The sealant sleeve 750can include a relatively large diameter proximal portion 752 surroundinga portion of the distal end 734 of the support member 730, e.g., sizedto abut or otherwise contact a hub or proximal end 783 of an introducersheath 780, such as that shown in FIG. 3D, and a relatively smalldiameter distal portion 754 surrounding the sealant 2, e.g., sized toenter the hub 783 and/or lumen 786 of the introducer sheath 780. The hub783 can include a cavity adapted to releasably receive the smalldiameter portion of the sealant sleeve. The cartridge 716 can beinitially provided such that the sealant sleeve 750 and sealant 2 arelocated immediately adjacent a positioning element 746 of thepositioning member 714.

The handle 723 can include an outer housing or shroud 772 surrounding aninner housing or frame 774 and one or more actuators 760-764 forallowing and/or causing movement of one or more components of theapparatus 710 relative to one another, as described further below. Asshown, the outer housing 772 can include a first opening or slot 773within which first and second actuators 760 and 762 are provided, and asecond slot 775 within which third actuator 764 is provided. The opening773 may include one or more features for interacting with first and/orsecond actuators 760, 762, as described further below.

The inner housing 774 may be slidable axially relative the outer housing772, e.g., between an initial, proximal position and a distal position.For example, the outer housing 772 may include clam-shell halves orother components that may be attached around the inner housing 774 suchthat cooperating rails and grooves (not shown) allow the inner housing774 to slide axially without substantial lateral motion. In an exemplaryembodiment, one or more elongate ribs or rails (not shown) may be moldedor otherwise provided on the inner surfaces of the outer housing 772that may be slidably received between rails or grooves (also not shown)in the inner housing 774.

The handle 723 can include a distal shroud 776 integrally formed with orotherwise extending from the outer housing 772. One or more detents orother features, e.g., a pair of tines 778, may be provided on the shroud776 for engaging the hub 723 to an introducer sheath, such as the sheath780 shown in FIG. 3D. For example, the sheath 780 may include a hub 783that includes a pair of pockets 783 a that extend axially along oppositesides of the hub 783. The tines 778 include tabs or detents 778 a thatmay be slidably received within the pockets 783 a, e.g., when theapparatus 710 is introduced into the sheath 780 during use, as describedbelow. The relative length of the tines 778 and pockets 783 a areconfigured such that the detents 783 a pass through the pockets 783 aand extend out the distal ends thereof. The detents 783 a may includeramped or tapered distal edges that facilitate insertion, and bluntproximal edges that may engage distal ends of the pockets 783 a toprevent the tines 778 from being withdrawn back through the pockets 783a, thereby coupling movement of the sheath 780 and outer housing 772 ofthe hub 723, also as described further below.

As can be seen in FIG. 3C, the apparatus 710 can include a rack andpinion arrangement. For example, as shown, a rack 766 may be coupled toa proximal end 732 of the support member 730 and slidably receivedwithin the outer and/or inner housings 772, 774. A pinion 768 may berotatably mounted to the inner housing 774 that is coupled to the rack766 by a plurality of interlocking teeth 766 a, 768 a. The second orsupport actuator 762, e.g., a button pivotably coupled to the innerhousing 774, is coupled to the pinion 768, e.g., by interlocking teeth762 b, 768 b, for selectively rotating the pinion 768. For example, asdescribed further below, the second actuator 762 may be depressed tocause the pinion 768 to rotate, thereby causing the rack 766 to advancedistally, thereby advancing the support member 730.

Optionally, as shown, a first or locking actuator 760 may be provided onthe hub 723 for preventing relative movement of the outer and inner/orhousings 772, 774 until activated and/or limiting movement of thesupport member 730. For example, as best seen in FIG. 3C, the lockingactuator 760 may be pivotably mounted to the inner housing 774 andinclude a distal end 760 a that abuts or otherwise engages a distal edge773 b of the opening 773 in the outer housing 772. As a result, theinner housing 774 may be substantially secured in the proximal positionand cannot be directed towards the distal position until the lockingactuator 760 is activated to disengage the distal end 760 a of theactuator 760 from the distal edge 773 b of the opening 773.

In addition or alternatively, the first actuator 760 may include adetent or other locking feature 760 b for selectively locking thesupport member 730 relative to the inner housing 774. For example, asshown in FIG. 3C, a detent 760 b extends inwardly from the firstactuator 760 that is not engaged with any other features. When the firstactuator 760 is activated, i.e., directed inwardly to disengage thedistal end 760 a of the actuator 760 from the distal edge 773 b of theouter housing 772, the detent 760 b may drop downwardly into the innerhousing 774. As discussed herein, once the inner and outer housingportions 774, 772 are movable relative to one another, the handle 723can be moved proximally causing the outer sheath 780 to retract anduncover the sealant.

Subsequently, when the support actuator 762 is subsequently activated,the rack 766 may advance, causing the support member 730 to tamp thesealant toward the arteriotomy, as described herein, until a distal end766 b of the rack 766 passes under the detent 760 b and the detent 760 bis captured in a pocket (not shown) therein. With detent 760 b capturedin the pocket, the rack 766 cannot be directed proximally, therebypreventing proximal movement of the support member 730 coupled to therack 766.

The apparatus 710 may also include a third or balloon retractionactuator 764, e.g., for selectively retracting the positioning element746 through the sealant 2 after deployment. For example, as shown inFIG. 3C, the third actuator 764 may be slidably mounted to the innerhousing 774 and may be selectively coupled to the hub 748 of thepositioning member 714.

Initially, the third actuator 764 may be coupled with the inner housing774 but may be decoupled from the inner housing 774 once the sealant 2has been deployed and/or tamped. For example, as best seen in FIG. 3C,the third actuator 764 may include a third arm 764 c that may bedecoupled from the inner housing 774 such that proximal movement of thethird actuator 764 relative to the outer and/or inner housings 772, 774causes similar proximal movement of the hub 748, thereby directing thepositioning element 746 proximally.

In addition, the third actuator 764 can include a second arm 764 b thatmay be slidably positioned adjacent a proximal end 766 c of the rack766. With the second arm 764 b positioned in this manner, the third arm764 c may remain coupled with the hub 748. When the rack 766 is directeddistally, e.g., by activating the second actuator 762, the second arm764 b may slide off the proximal end 766 c of the rack 766, therebydecoupling the third arm 764 c from the inner housing 774. For example,as shown, a spring or other biasing mechanism 764 a may be provided onthe third actuator 764 (or optionally, the outer housing 772) forbiasing the second arm 764 b outwardly when the rack 766 is directeddistally to clear the second arm 764 b from the proximal end 766 c ofthe rack 766. In addition, the spring or biasing mechanism 764 a mayrequire that the actuator be depressed in order to decouple the thirdarm 764 c from the inner housing thereby preventing inadvertent movementof the positioning element 746. Thereafter, the third actuator 764 maybe directed proximally to retract the hub 748 and the positioningelement 746.

The apparatus 710 may be used to deliver the sealant 2 into a puncture,e.g., communicating with a body lumen within a patient's body.Initially, the introducer sheath 780 shown in FIG. 3D may be positionedthrough the puncture into the body lumen.

Optionally, the introducer sheath 780 may be provided as part of anintroducer kit, e.g., including a dilator 790 and a guidewire 799,and/or a system also including the apparatus 710. The dilator 790 mayinclude a proximal end 792 and a distal end 794 sized to be slidablyreceived through the lumen 786 of the introducer sheath 780, e.g.,terminating a tapered, atraumatic and/or other distal tip to facilitateintroduction of the dilator 790 and introducer sheath 780 into apuncture (not shown), e.g., over the guidewire 799. As shown, thedilator 790 can include a proximal housing 796 include tines 798 anddetents 798 a configured similar to the distal shroud 776 of theapparatus 710. The dilator 790 may be directed into the hub 783 andlumen 786 of the introducer sheath 780 until the tines 798 enter and thedetents 798 a exit the passages 783 a in the hub 783.

Thus, the dilator 790 and introducer sheath 780 may be coupled togethersuch that the guidewire 799 (already placed through a puncture into abody lumen, not shown, as described elsewhere herein) may be backloadedinto the distal end 794 and lumen 796 of the dilator 790 to introducethe dilator 790 and introducer sheath 780 into the puncture. Once theintroducer sheath 780 is positioned as desired, the tines 798 may besqueezed inwardly to disengage the detents 798 a from the pockets 783 aand allow the dilator 790 to be withdrawn from the lumen 796 of theintroducer sheath 790. The introducer sheath 780 may then be used toaccess the body lumen and perform one or more procedures, as describedelsewhere herein.

When it is desired to seal the puncture, any instruments introducedthrough the introducer sheath 780 may be removed and the apparatus 710may be prepared, e.g., as shown in FIGS. 3A and 3B. With the positioningelement 746 collapsed, the distal end 744 of the positioning member 714may be directed into the hub 783 of the introducer sheath 780, throughthe lumen 786, and into the body lumen. Because the sealant sleeve 750and sealant 2 are located immediately adjacent the positioning element746, as the distal end 744 enters the introducer sheath 780, the sleeve750 may contact the introducer sheath 780, which may prevent furtheradvancement of the sleeve 750. For example, the distal portion 754 ofthe sleeve 750 may at least partially enter the hub 783 of theintroducer sheath 780 and the proximal portion 752 of the sleeve 750 mayabut the hub 783, thereby preventing further advancement of the sleeve750. If the sleeve 450 is releasably attached to the support member 730,advancement of the positioning member 714 may release the sleeve 750from the distal end 734 of the support member 730.

The positioning member 714 may be advanced further into the introducersheath 780, whereupon the sleeve 750 may remain substantially stationaryrelative to the introducer sheath 780 and, consequently, slideproximally over the support member 730. Thus, the distal end 734 of thesupport member 730 may exit the distal portion 754 of the sleeve 750 andenter the introducer sheath lumen 786, thereby ejecting the sealant 2from the sleeve 750 and into the sheath lumen 786. Optionally, thedistal portion 754 of the sleeve 750 may have sufficient length and/orother features to at least partially open the valve(s) (not shown)within the introducer sheath hub 783, e.g., to facilitate the sealant 2and distal end 734 of the support member 730 being advanced into theintroducer sheath lumen 786. Thus, the sleeve 750 may protect thesealant 2 until the sealant 2 passes through the hub 783 and any valvestherein, into the lumen 786 of the introducer sheath 780.

The positioning member 714 may then be advanced until the positioningelement 746 is disposed beyond the distal end 784 of the introducersheath 780, i.e., within the body lumen. As this occurs, the tines 778on the housing shroud 776 may be aligned with and enter the pockets 783a on the sheath hub 783, e.g., until the detents 778 a engage the distalends of the pockets 783 a, as described above. With the detents 778 aengaged with the pockets 783 a, the introducer sheath 780 and outerhousing 772 may be coupled together such that they move together.

The relative length of the positioning member 714 and the introducersheath 780 may be configured such that the sealant 2 remains within thesheath lumen 786, e.g., proximal to the distal end 784 of the introducersheath 780, while the positioning element 746 is exposed beyond thedistal end 784. The positioning element 746 may then be expanded, e.g.,by inflating the positioning element 746 using fluid from the syringe148. The entire apparatus 710 and introducer sheath 780 may then beretracted (regardless of whether the apparatus hub 723 or the sheath hub783 is manipulated) until the expanded positioning element 746 contactsthe wall of the body lumen adjacent the puncture.

Once properly positioned, the first actuator 760 may be activated todecouple movement of the outer and inner members 772, 774. For example,while holding the outer housing 772, the first actuator 760 may bepressed inwardly to disengage the distal end 760 a of the first actuator760 from the distal end 773 b of the outer housing 772, and then theouter housing 772 may be retracted proximally, i.e., away from thepatient and puncture. With the inner housing 774 coupled to thepositioning member 714 and support member 730, this action causes theinner housing 774 to slide within the outer housing 772, i.e., from theproximal position (shown in FIGS. 3A-3C) to the distal position, therebyretracting the introducer sheath 780 relative to the support member 730and exposing the sealant 2 within the puncture adjacent the positioningelement 746.

With the inner housing 774 in the distal position, the second actuator762 may be activated to advance the support member 730, e.g., to tamp orcompress the sealant 2 against the expanded positioning element 746and/or outer wall of the body lumen, e.g., over an arteriotomy. Forexample, with particular reference to FIG. 3C, the second actuator 762may be pressed inwardly, thereby rotating the pinion 768, advancing therack 766, and consequently advancing the support member 730 to directthe distal end 734 towards the positioning element 746 and compress thesealant 2 therebetween.

Optionally, the second actuator 762 may include one or more features,e.g., tabs or detents 762 a that may be engaged with the outer housing772 when the second actuator 762 is fully depressed. For example, asshown in FIGS. 3A and 3B, the opening 773 in the outer housing 772 mayinclude one or more pockets or recesses 773 a that may be aligned withthe tabs 762 a on the second actuator 762 when the inner housing 774 hasbeen directed fully to the distal position. With the tabs 762 a receivedwithin the pockets 773 a, the inner housing 774 cannot be movedproximally relative to the outer housing 772, thereby securing the outerand inner housings 772, 774 relative to one another.

Once the sealant 2 has been exposed for sufficient time and/or tamped bythe support member 730, the positioning element 746 may be collapsed,and the positioning member 714 withdrawn from the body lumen, e.g.,pulling the collapsed positioning element 746 through the sealant 2 andsupport member 730. For example, the positioning element 746 may bedeflated using the syringe 148, and then the third actuator 764 may beactivated to withdraw the collapsed positioning element 746 through thesealant 2 and into the distal end 734 of the support member 730.

Optionally, as described above, the third actuator 764 may remaincoupled with the inner housing 774 until the rack 766 is advancedsufficiently to release the third arm 764 c of the third actuator.Thereafter, proximal movement of the third actuator 764 relative to theouter and inner housings 772, 774 causes the hub 748 and the entirepositioning member 714 to also move proximally, thereby withdrawing thepositioning element 746 through the sealant 2 into the distal end 734 ofthe support member 730. The length of the slot 775 in the outer housing772 may be configured to withdrawn the positioning element 746 a desireddistance into the distal end 734.

Once the positioning element 746 is withdrawn through the sealant 2, theentire apparatus 710 may be withdrawn to remove the support member 730from the puncture, leaving the sealant 2 within the puncture.

FIGS. 4A-4F schematically illustrate a method of delivering a sealantfrom another apparatus 810 to an arteriotomy site. The apparatus 810 caninclude any of the features described in connection with the apparatus710. For example, the apparatus 810 can include a sealant 2 positionedat a distal portion of a positioning assembly 814. The positioningassembly 814 extends through the puncture and into the vessel, such thatthe positioning element 856 is within the vessel lumen and the sealant 2is outside the vessel wall (FIG. 4A). Expanding the positioning element846 secures the apparatus 810 relative to the arteriotomy site (FIG.4B). Withdrawing a sheath 880 exposes the sealant 2 to the arteriotomysite (FIG. 4C), and advancing a support member 830 tamps the sealant 2(FIG. 4D). After the positioning element 846 deflates (FIG. 4E), thepositioning element 846 can move proximally through the sealant 2 (FIG.4F), leaving the sealant 2 outside the vessel. The support member 830can maintain the position of the sealant 2, while the positioningelement 846 is withdrawn. After the positioning element 846 iswithdrawn, the entire apparatus 810, including the sheath 880 and thepositioning assembly 814 can be withdrawn from the patient. Theapparatus 810 and methods of using the apparatus 810 are described indetail below.

As shown in FIGS. 4A through 4F, the apparatus 810 can include a handle823. The handle 823 can include an outer housing 872 and an innerhousing 874. The outer housing 872 can move relative to the innerhousing 874, for example, when the sheath 880 moves proximally relativeto the positioning assembly 814.

The handle 823 can include one or more actuators for controlling theapparatus 810. Each actuator can control one or more functions of theapparatus 810. The one or more actuators can be positioned anywherealong the handle 823. In FIGS. 4A through 4F, the actuators 860, 862,864, and 848 are positioned along the handle 823 based on the proceduralstep each actuator controls. The configuration of actuators shown inFIGS. 4A through 4F reduces confusion associated with operating theapparatus 810 by only requiring the user to move his/her hand proximallyfor each subsequent step of the procedure. Although FIGS. 4A through 4Eillustrate four actuators 860, 862, 864, and 848, fewer or additionalactuators may be used to perform the same functions.

The apparatus 810 can include the inflation line 48 c. The inflationline 48 c is in fluid communication with the positioning element 846.The inflation line 48 c connects to the syringe 148 or other device fordelivering fluid to the positioning element 846.

The apparatus 810 can include a first actuator 860 to control fluid flowthrough the inflation line 48 c. The first actuator 860 moves between anopen position and a closed position. As shown in FIG. 4A, when the firstactuator 860 is in the open position, the syringe 148 can deliver afluid through the inflation line 48 c to expand the positioning element846. In FIG. 4B, the first actuator 860 moves to the closed position andrestricts fluid flow through the inflation line 48 c to maintain theexpanded state of the positioning element 846. After the positioningelement 846 expands, the apparatus 810 moves proximally so thepositioning element 846 is adjacent to the arteriotomy.

The apparatus 810 can include a second actuator 862 to control movementof the sheath 880 relative to the positioning assembly 814. The secondactuator 862 moves between a first position and a second position. Inthe first position (FIGS. 4A and 4B), the sheath 880 cannot moverelative to the positioning assembly 814, thus preventing inadvertentexposure of the sealant 2. Moving the second actuator 862 from the firstposition to the second position, as shown in FIG. 4C, permits the sheath880 to move relative to the positioning assembly 814. Retracting thesheath 880 exposes the sealant 2 to the arteriotomy site, while thepositioning assembly 814 remains stationary. Retracting the sheath 880can also cause a portion of the outer housing 872 to at least partiallycover the second actuator 862.

The apparatus 810 can include a locking mechanism to prevent the innerhousing 874 from moving relative to the outer housing 872. As the sheath880 retracts, the outer housing 872 moves between a first position and asecond position. When the outer housing 872 is in the first position(FIGS. 4A and 4B), the inner housing 874 can move relative to the outerhousing 872. When the outer housing 872 is in the second position (FIG.4C), the inner housing 874 is unable to move proximally relative to theouter housing 872.

As shown by FIGS. 4C and 4D, the apparatus 810 can include a thirdactuator 864. The third actuator 864 moves between a first position anda second position. Moving the third actuator 864 from the first positionto the second position advances the support member 830 to tamp thesealant 2. Tamping the sealant 2 can prevent substantial movement of thesealant 2 and facilitate hemostasis.

Moving the third actuator 864 from the first position to the secondposition can release a retraction lock 816. The retraction lock 816prevents the positioning assembly 814 from inadvertently retractingprior to tamping the sealant 2. Releasing the retraction lock 816permits at least a portion of the positioning assembly 814 to moveproximally relative to the support member 830.

The apparatus can include a fourth actuator 848 capable of movingbetween a first position and a second position. Unlocking the retractinglock 816 permits movement of the fourth actuator 848. Moving the fourthactuator 848 from the first position to the second position retracts atleast a portion the positioning assembly 814 relative to the supportmember 830.

In FIG. 4E, the first actuator 860 moves to the open position to permitfluid flow through the inflation line 48 c. When the first actuator 860is in the open position, the syringe 148 can deflate the positioningelement 846. In FIG. 4F, the positioning member 814 is retracted throughthe sealant 2, so the entire apparatus 810 can be removed from thepatient.

As described above, the apparatus 810 can include an actuation mechanismto control fluid flow to the positioning element 846. The actuationmechanism can include any of the features described below in connectionwith FIGS. 5A-7B, alone or in combination with each other.

FIGS. 5A and 5B depict the first actuator 860 a moving between theopening position and the closed position. FIGS. 5A-1 and 5B-1 illustratea cross-sectional view of the inflation line 48 a. The outer housing 872a of the handle includes an opening through which a portion of the firstactuator 860 a extends. In FIGS. 5A and 5B, the first actuator 860 a isa valve, but the first actuator 860 a and the valve can also be separatecomponents. The valve can include a pinch mechanism to restrict fluidflow through the inflation line 48 a.

The first actuator 860 a can move between the open position (FIG. 5A)and the closed position (FIG. 5B). In the open position, fluid can flowthrough inflation line 48 a. In the closed configuration, fluid cannotflow through the inflation line 48 a. Although FIGS. 5A and 5B depictthe first actuator 860 a as a rocker, the first actuator 860 a can takeon other shapes.

FIGS. 6A and 6B depict an apparatus having the first actuator 860 b anda deflation actuator 866 b. FIGS. 6A-1 and 6B-1 illustratecross-sectional views of the inflation line 48 b. A linkage portion 867b connects the first actuator 860 b to the deflation actuator 866 b.Although the linkage portion 867 b shown in FIGS. 6A and 6B includesmultiple link members, the linkage portion 867 b may only include onelink member (see FIGS. 6E-6F). The outer housing 872 b includes twoopenings through which a portion of the first actuator 860 b and thedeflation actuator 866 b extend.

Similar to FIGS. 5A and 5B, the first actuator 860 b can move from afirst position to a second position to restrict fluid flow through theinflation line 48 b. Moving the first actuator 860 b from the firstposition to the second position causes the deflation actuator 866 b tomove from a first position to a second position. Moving the deflationactuator 866 b from the second position to the first position causes thefirst actuator 860 b to move from the second position to the openposition to permit fluid flow through the inflation line 48 b.

Similar to FIGS. 6A and 6B, FIGS. 6C and 6D, can include a firstactuator 860 c and a deflation actuator 866 c connected by linkageportion 867 c. The linkage portion 867 c can include one or more linkmembers. Unlike FIGS. 6A and 6B, the first actuator 860 c and thedeflation actuator 866 c are different from the valve 884 c. Forexample, the valve 884 c can be positioned distal to the first actuator860 c and the deflation actuator 866 c.

The first actuator 860 c can move from a first position to a secondposition to close the valve 884 c and restrict fluid flow through theinflation line. Moving the first actuator 860 c from the first positionto the second position causes the deflation actuator 866 c to move froma first position to a second position. Moving the deflation actuatorfrom the second position to the first position causes the first actuator860 c to move from the second position to the first position and openthe valve 884 c.

Similar to FIGS. 6A-D, FIGS. 6E and 6F can include a first actuator 860d and a deflation actuator 866 d connected by linkage portion 867 d.Unlike FIGS. 6A and 6B, the linkage portion 867 d only includes one linkmember. In addition, similar to FIGS. 6C and 6D, the first actuator 860d and the deflation actuator 866 d are different from the valve 884 d.For example, the valve 884 d can be positioned distal to the firstactuator 860 d and the deflation actuator 866 d.

The first actuator 860 d can move from a first position to a secondposition to close the valve 884 d and restrict fluid flow through theinflation line. Moving the first actuator 860 d from the first positionto the second position causes the deflation actuator 866 d to move froma first position to a second position. Moving the deflation actuatorfrom the second position to the first position causes the first actuator860 d to move from the second position to the first position and openthe valve 884 d.

The apparatus having the first actuator and the deflation actuator maybe useful to minimize confusion associated with operating the apparatus.For example, if the apparatus includes additional actuators to controlsteps performed between inflating and deflating the positioning element,the additional actuators can be positioned along the handle between thefirst actuator and the deflation actuator. The actuators can bepositioned based on the procedural step each actuator controls, suchthat the user can move his/her hand proximally for each subsequent stepof the procedure. The deflation actuator may be positioned proximally ofthe additional actuators because deflating the positioning element isthe final step before withdrawing the apparatus.

As described above, the first actuator and the valve can be separatecomponents. As shown in FIGS. 7A-B, the first actuator 960 moves betweena first position and a second position to control the position of thevalve 961. Moving the first actuator 960 from the first position (FIG.7A) to the second position (FIG. 7B) moves the valve 961 from an openposition to a closed position. In the closed position, the valve 961restricts fluid flow through the inflation line 948. FIGS. 7A-1 and 7A-2illustrate cross sectional views of the inflation line 948 moving froman open configuration to a closed configuration. Moving the firstactuator 960 from the second position to the first position moves thevalve 961 from the closed position to the open position, thus permittingfluid to flow through the inflation line 948.

The first actuator 960 can be a lever. A pin connects the first actuator960 to the valve 961. The valve 961 can be a sliding valve having apinch mechanism to restrict fluid flow through the inflation line 948.Moving the first actuator 960 between the first position and the secondposition slides the valve 961 linearly between the open position and theclosed position. Although FIGS. 7A-B depict the first actuator 960 as alever, the apparatus can include any other mechanism capable of movingthe valve 961, such as a rack and pinion arrangement, a cam mechanism,or any other actuator.

The apparatus 810 can include the second actuator 862 to controlmovement of the sheath 880 relative to the positioning assembly 814. Theouter housing 872 can include an opening through which at least aportion of the second actuator 862 extends. As shown in FIGS. 8A and 8B,the second actuator 862 can be a spring-actuated button.

The second actuator 862 a moves between a first position (FIG. 8A) and asecond position (FIG. 8B). When the second actuator 862 a is in thefirst position, the second actuator 862 a prevents proximal movement ofthe sheath relative to the positioning assembly. When the secondactuator 862 a is in the second position, the sheath can move proximallyrelative to the positioning assembly. As the sheath moves proximally,the outer housing 872 a prevents the second actuator 862 a from movingto the first position. Although the second actuator 862 a illustrated inFIGS. 8A and 8B includes a spring mechanism 868 a, any other lockingmechanism described herein can be used to control movement of the sheathrelative to the positioning assembly.

As shown in FIGS. 9A and 9B, the second actuator 862 b can include adetent 869 b. When the second actuator 862 b is in the first position(FIG. 9A), the sheath cannot move relative to the positioning assembly.When the second actuator 862 b is in the second position (FIG. 9B), thedetent 869 b locks the second actuator 862 b in a depressed position,thus permitting the sheath to move proximally relative to thepositioning assembly. As the sheath moves proximally, the outer housing872 b moves over the second actuator 862 b and keeps the second actuator862 b depressed.

The apparatus 810 can also include a mechanism to restrict the distancethe sheath 880 can move relative to the positioning assembly 814. Forexample, as shown in FIGS. 8B and 8B, the sheath can only move until thedistal end of the inner housing 874 abuts the distal end of the outerhousing 872 or a different feature in the handle 823.

As described earlier, the handle 823 can include a locking mechanism tolock the inner housing 874 relative to the outer housing 872. As shownin FIGS. 4A-4F, the locking mechanism can include one or moreprotrusions 863 positioned along an inner wall of the outer housing 872and one or more resilient members 875 positioned on the inner housing874. As the sheath 880 moves proximally, the one or more resilientmembers 875 flex inwardly and move past the one or more protrusions 863.After the one or more resilient member 875 move past the one or moreprotrusions 863, the inner housing 874 is unable to move proximallyrelative to the outer housing 872.

In FIGS. 10A and 10B, the locking mechanism includes at least twoprotrusions 863 along the inner wall of the outer housing 872 and atleast two resilient members 875 positioned at a proximal end of theinner housing 874. The resilient members 875 are capable of flexinginward to move distally past the one or more protrusions 863. As thesheath 880 is withdrawn, the resilient members 875 flex inward and movepast the protrusions 863. After the resilient members 875 move past theprotrusions, the inner housing 874 cannot move proximally relative tothe outer housing 872.

Alternatively, the locking mechanism can include one or more protrusions863 positioned on the inner housing 874 and one or more resilientmembers positioned along the inner wall of the outer housing 872. Otherlocking mechanisms described herein can also be used to lock the innerhousing 874 relative to the outer housing 872.

The apparatus 810 can include a mechanism to release the positioningassembly 814 from the inner housing 874. Releasing the positioningassembly 814 permits the positioning assembly 814 to move proximallywhile maintaining the position of the support member 830. Alternatively,the apparatus 810 can include a mechanism to release the inner housingfrom the outer housing.

FIGS. 11A through 11C illustrate a mechanism to prevent the supportmember 830 from advancing prior to retracting the outer sheath 880. Asshown in FIG. 11A, locking mechanism can be a tab 873 that preventsmovement of the third actuator 864. However, after the sheath 880 movesproximally (FIG. 11B), the tab 873 moves proximally to enable movementof the third actuator 864 from a first position (FIG. 11B) to a secondposition (FIG. 11C). Other locking mechanisms described herein can alsobe used to prevent the support member 830 from advancing.

FIGS. 12A and 12B illustrate one mechanism for advancing the supportmember 830. Moving the third actuator 864 from the first position to thesecond position causes a linkage element 865 to extend and advance thesupport member 830. The support member 830 can extend until a portion ofthe support member 830 abuts a feature of the handle, such as the distalend of the inner housing 874 or the outer housing 872. The distance thesupport member 830 can advance may also be limited by the distance thelinkage element 865 can extend.

FIGS. 13A and 13B illustrate the apparatus 810 having a spring member870. Moving the third actuator 864 from the first position to the secondposition causes the spring member 870 to expand and advance the supportmember 830 distally. The support member 830 can extend until a portionof the support member 830 abuts a feature of the handle, such as thedistal end of the inner housing 874 or the outer housing 872. Thedistance the support member 830 can advance may also be limited by thedistance the spring member 870 can expand. Other mechanisms can be usedto advance the support member 830, such as the rack and pinionarrangement described in connection with apparatus 710 or any otheractuator.

As described earlier, the apparatus 810 can include a retraction lock816 to lock the position of the positioning assembly 814 relative to theinner housing 874. Moving the third actuator 864 from the first positionto the second position can release the retraction lock 816 by moving alever 817 from a first position to a second position. When the lever 817is in the second position, the positioning assembly 814 can moverelative to the outer housing 872. Retracting the fourth actuator 848 ofthe positioning assembly 814 causes the positioning assembly 814 toretract past the sealant 2. The support member 830 can retain theposition of the sealant 2 while the positioning assembly 814 retracts.After the positioning element 814 retracts, the entire apparatus 810 canbe removed from the patient. Other locking mechanisms described hereincan also be used to lock the position of the positioning assembly 814relative to the inner housing 874.

FIGS. 15A-15F schematically illustrate a method of delivering a sealantsimilar to the method shown in FIGS. 4A-4F. However, as describedearlier, the handle 823 does not have to include four actuators 860,862, 864, and 848. For example, as shown in FIGS. 15A-15F, the handledoes not include the first actuator 860. Instead, the inflation line 48c includes a valve 882. The valve 882 moves between a first position anda second position. When the valve 882 is in the first position, as shownin FIG. 15A, fluid can flow from the syringe to the positioning member846. When the valve 882 moves from the first position to the secondposition, as shown in FIG. 15B, fluid can no longer flow from thesyringe to the positioning member 846.

FIGS. 16A-B illustrate an apparatus 1010 for delivering a sealant to anarteriotomy site. The apparatus 1010 can include any of the features ofthe sealant delivering apparatuses discussed herein. For example, theapparatus 1010 can include a positioning assembly 1014 having a handle1023 and a positioning element 1046. At least a part of the positioningassembly 1014 can extend through a sheath 1080. An inflation line 48 ccan extend from the positioning element 1046 to a syringe 148 or anyother mechanism for inflating and deflating the positioning element1046. The inflation line 48 c can include a first actuator 1082 forcontrolling fluid flow to the positioning element 1046. The handle 1023can include a second actuator 1062 to permit the sheath 1080 to retractrelative to the positioning element 1014, a third actuator 1064 toadvance a support member (not shown), and/or a fourth actuator 1048 forretracting at least a portion of the positioning assembly 1014 relativeto the sheath 1080.

The sheath 1080 can include a mechanism to indicate when a distalportion of the sheath enters a vessel. For example, the sheath 1080 caninclude one or more inlet openings 1089 at a distal portion of thesheath 1080. As the sheath 1080 enters the vessel, blood can flow intothe openings 1080 and out of an outlet opening outside of the user.

As shown in FIG. 16A, the sheath 1080 can also include a hub 1083 forengaging the handle 1023. For example, the hub 1083 can include one ormore openings for engaging one or flanges of the handle, or vice versa.Depressing the sheath hub 1083 can release the sheath 1080 from thepositioning assembly 1014. The sheath hub can also include a catch toengage the sealant sleeve (not shown). As the positioning assembly 1014enters the sheath 1080, the sheath catch can engage the sealant sleeveto transfer the sealant from the sealant sleeve to the sheath 1080.

The apparatus 1010 can also include an inflation indicator 1002. Theinflation indicator 1002 indicates when the positioning element 1046 isinflated to a pre-determined pressure and signals a user to seal theinflation line 48 c. As shown in FIG. 16B, the inflation line connectsto a plunger system 1004. As the positioning element 1046 inflates, theshaft member 1005 moves from a first position to a second position. Asthe shaft member 1005 move to the second position, the indicator 1002moves from a first position to a second position. When the indicator1002 is in the second position, the positioning element 1046 is fullyinflated. As the positioning element 1046 deflates, the shaft member1005 moves from the second position to the first position and theindicator 1002 moves from the second position to the first position.When the indicator 1002 is in the first position, the positioningelement 1046 is not fully inflated.

The indicator 1002 can include a first indicator 1003 a and a secondindicator 1003 b. When the positioning element 1046 is not fullyinflated, the first indicator 1003 a can be seen through the opening1006 of the handle 1023. When the positioning element 1046 is fullyinflated, the second indicator 1003 b can be seen through the opening1006 of the handle 1023.

Any of the sealant delivering apparatuses discussed herein can be acomponent of a system including, but not limited to, a guidewire or adilator. The guidewire can include any of the features described inconnection with guidewire 799 described above. The dilator can alsoinclude one or more of the features described in connection with thedilator 790 described above and/or dilator 1190 (FIGS. 17A-17D) ordilator 1290 (FIGS. 18A-18C) described below.

As described shown in FIGS. 17A-18C, the dilator can contain a fluidlumen that allows blood to flow from an inlet opening near the distaltip of the dilator to an outlet opening near the proximal end of thedilator. Blood flow exits the proximal port when the tip of the sheathenters the vessel. The sheath can then further advanced to ensure thatthe distal tip of the sheath is in the vessel lumen.

As shown in FIGS. 17A-17D, the dilator 1190 includes an elongatestructure 1191 having a lumen extending therethrough. The dilator 1190can also include a proximal portion 1193 having a dilator hub 1196 forengaging the sheath and/or a distal portion 1192 having a tapered end.As shown in FIG. 17A, the dilator hub 1196 can be U-shaped. The U-shapeddilator hub 1196 defines an opening for receiving a proximal end of thesheath. The dilator hub 1196 can also include hub members 1197 a, 1197 bconfigured to engage an outer surface of the sheath. The dilator hub1196 can also include one or more flanges to engage a correspondingfeature of the sheath. For example, as shown in FIG. 17A, the hubmembers 1197 a, 1197 b can include flanges 1198 a, 1198 b to and/or thehub 1196 can include flanges 1199 a, 1199 b near a top surface of thedilator hub.

The dilator 1190 can also include a bleed back feature to help determinewhen the distal portion 1192 of the dilator 1190 enters a vessel. Forexample, the dilator 1190 can include one or more inlet openings 1194 ata distal portion 1192 of the dilator 1190. As shown in FIG. 17A, thedilator 1190 can include two inlet openings 1194. The inlet openings1194 can be positioned proximal to the tapered portion of the elongatestructure 1191 and/or along the same plane transverse to thelongitudinal axis of the dilator 1190. The dilator 1190 can also includeone or more outlet openings 1195 positioned proximal to the dilator hub1196. As shown in FIG. 17A, the dilator 1190 can include one outletopening 1195. The outlet opening 1195 can be positioned along the sameplane as one of the inlet openings 1194. The dilator hub can include adirection feature 1197 for indicating the direction the blood flow willexit. As shown in FIG. 17C, the direction feature 1197 can be an arrowalong a top surface of the dilator hub 1196.

The lumen extending through the elongate structure 1191 can have avarying diameter. For example, the lumen can have a first diameter 1189at the distal portion 1192 and proximal portion 1193 of the elongatestructure 1192 and a second diameter 1188 between the distal portion1192 and proximal portion 1193. The first diameter 1189 can be less thanthe second diameter 1188. The first diameter 1189 can include a diameterthat is larger than the outer diameter of the guide wire and smallerthan the second diameter 1188. In some embodiments, the first diameter1189 at least about half of the second diameter 1188 and/or less than orequal to about three-fourths of the second diameter 1188. In someembodiments, the first diameter 1189 is about two-thirds the seconddiameter 1188.

The lumen diameter can vary while the outer diameter of the elongatestructure 1191 remains the same. For example, the proximal portion 1193can have an outer diameter that is the same as a portion between theproximal portion 1193 and the distal portion 1192. The varying diameterpermits the proximal portion 1193 and the distal portion 1192 of thedilator 1190 to form a seal around the guide wire. As such, blood onlyflows through the inlet openings 1194 to the outlet opening 1195.

FIGS. 18A-C illustrate a dilator 1290 includes an elongate structure1291 having a lumen extending therethrough. The dilator 1290 can alsoinclude a proximal portion 1293 having a dilator hub 1296 for engagingthe sheath and/or a distal portion 1292 having a tapered end. As shownin FIG. 18A, the dilator hub 1296 can include hub members 1297 a, 1297 bconfigured to engage the sheath. For example, the sheath can includecorresponding features for receiving the hub members 1297 a, 1297 b. Thehub members 1297 a, 1297 b can also include one or more flanges toengage a corresponding feature of the sheath. For example, as shown inFIG. 18A, the hub members 1297 a, 1297 b, can include outward facingflanges 1298 a, 1298 b and/or inward facing flanges 1299 a, 1299 b. Theflanges can be positioned near (e.g., flange 1299 a, 1299 b) and/or at adistal portion (e.g., flange 1298 a, 1298 b) of the hub members 1297 a,1297 b.

The dilator 1290 can also include a bleed back feature to help determinewhen the distal portion 1292 of the dilator 1290 enters a vessel. Forexample, the dilator 1290 can include one or more inlet openings 1294 ata distal portion 1292 of the dilator 1290. As shown in FIG. 18A, thedilator 1290 can include two inlet openings 1294. The inlet openings1294 can be positioned proximal to the tapered portion of the elongatestructure 1291 and/or along the same plane transverse to thelongitudinal axis of the dilator 1290. The dilator 1290 can also includeone or more outlet openings 1295. As shown in FIG. 18A, the dilator 1290can include one outlet opening 1295. In some embodiments, the outletopening 1295 can be positioned along the same plane as one of the inletopenings 1294. In other embodiments, the outlet opening 1295 can bepositioned along a different plane from any of the inlet openings 1294.For example, the outlet opening 1295 can positioned along a plane thatis perpendicular to the plane passing through the inlet openings 1294.

The lumen extending through the elongate structure 1291 can have avarying diameter. For example, the lumen can have a first diameter 1289at the distal portion 1292 and proximal portion 1293 of the elongatestructure 1292 and a second diameter 1288 between the distal portion1292 and proximal portion 1293. The first diameter 1289 can be less thanthe second diameter 1288. The first diameter 1289 can include a diameterthat is larger than the outer diameter of the guide wire and smallerthan the second diameter 1288. In some embodiments, the first diameter1289 at least about half of the second diameter 1288 and/or less than orequal to about three-fourths of the second diameter 1288. In someembodiments, the first diameter 1289 is about two-thirds the seconddiameter 1288.

The lumen diameter can vary while the outer diameter of the elongatestructure 1291 remains the same. For example, the proximal portion 1293can have an outer diameter that is the same as a portion between theproximal portion 1293 and the distal portion 1292. The varying diameterpermits the proximal portion 1293 and the distal portion 1292 of thedilator 1290 to form a seal around the guide wire. As such, blood onlyflows through the inlet openings 1294 to the outlet opening 1295.

In any of the above mentioned dilators, the diameter of any of theoutlet opening can be smaller than a diameter of any of the inletopenings. For example, the diameter of any of the outlet opening can beless than or equal to half of the diameter of any of the inlet openings.

FIGS. 19A-19E illustrate how any of the above mentioned positioningassemblies can engage a sheath. FIG. 19A illustrates an apparatus 1310before the apparatus 1310 is delivered through the sheath 1380. Theapparatus 1310 can include any of the features of the sealant deliveringapparatuses described above. The positioning assembly 1314 can engagethe sheath 1380, such that movement of the handle 1323 can also move thesheath 1380. For example, the handle 1323 can include a shroud portion1376 configured to engage a hub 1383 of the sheath 1380. As shown inFIG. 19A, the shroud 1376 can include two tines 1378, and each tine 1378can include a barb 1379 positioned at a distal portion of the tine 1378.The hub 1383 can include openings 1385 to receive the tines 1378. Otherfastening mechanisms without tines can also be used to couple theapparatus 1310 with the sheath 1380, such as a snap fit, interferencefit, or screw mechanism.

As described above, the sealant 1302 is initially positioned at a distalportion of the positioning assembly 1314 (FIG. 19A). Before thepositioning assembly 1314 enters the sheath 1380, a sealant sleeve 1350covers the sealant 1302 to prevent exposure of the sealant 1302 to theenvironment. The sealant sleeve 1350 can include any of the features ofthe sealant sleeve 450 described above. As the positioning assembly 1314enters the sheath 1380, the sealant 1302 is transferred from the sealantsleeve 1350 to the sheath 1380 (FIG. 19B). The sheath hub 1383 and/orshroud 1376 retains the sealant sleeve 1350. The sheath hub 1383 and/orshroud 1375 retain the sealant sleeve 1350 even as the sheath 1380 isretracted (FIG. 19C) or the sealant 1302 is tamped using the supportmember 1330 (FIG. 19D).

In some embodiments, as shown in FIG. 20, the tines engage an exteriorportion of the sheath hub 1483. For example, the hub 1483 can includegrooves 1486 configured to engage the barbs 1478. The sheath hub 1483can also include an inner diameter that is smaller than an outerdiameter of the sealant sleeve 1450 to facilitate the sealant transferfrom the sealant sleeve 1450 to the sheath 1480.

FIGS. 21A-21I describe a method of using the system including any of thesealant delivering apparatuses and dilators described herein. The methodcan include one or more of the steps described below. A proceduralsheath (not shown) can be inserted through a puncture 1504 in a vesselwall 1506 to gain access to a vessel lumen. After the guidewire 1502extends through the procedural sheath and into the vessel, theprocedural sheath can be removed from the tissue tract, leaving theguidewire 1502 in place with the distal tip of the guidewire 1502positioned within the vessel lumen. The dilator 1508 can then beadvanced through the closure system sheath 1510, and the dilator-sheathassembly can be advanced over the guidewire 1502 (FIG. 21A). Any of themechanisms described herein can be used to determine when thedilator-sheath assembly enters the vessel lumen (e.g., a bleed back porton the dilator and/or sheath).

After a distal end of the sheath 1510 extends into the vessel lumen, thedilator 1508 and guidewire 1502 can be proximally retracted and removedleaving the distal end of the sheath 1510 inside the vessel lumen (FIG.21B). A positioning assembly 1512 can then be introduced into theproximal end of the sheath 1510 and advanced distally through the sheath1510 (FIGS. 21C-E). As described herein, the positioning assembly 1512can include a sealant 1516 positioned at a distal portion of thepositioning assembly 1512 prior to entering the sheath 1510. After apositioning element 1514 extends out from the distal end of the sheath1510 and into the vessel lumen, the positioning element 1514 can beexpanded within the vessel lumen (FIG. 21F).

The positioning assembly 1512 can then be withdrawn to seat thepositioning element 1514 against the vessel puncture 1504, and thesealant 1516 and sheath 1510 outside the vessel wall 1506 (FIG. 21G).The sheath 1510 can then be partially retracted to expose the sealant1516 (FIG. 21H). The support member 1518 can then be advanced to tampthe sealant 1516 against the vessel wall 1506 (FIG. 21I). Thepositioning element 1514 may thereafter be reduced in cross-section(e.g. deflated) and proximally retracted through the sealant 1516. Thesupport member 1518 may be left in position against the sealant duringproximal retraction of the positioning element 1514, to maintain thelocation of the sealant. After removal of the positioning element 1514,the support member 1518 and sheath 1510 if still present within thetissue tract may be removed from the patient, leaving the sealant 1516positioned adjacent the vessel wall 1506.

In one implementation of the invention, the positioning element 1514 isan inflatable balloon carried on a distal region of an elongate ballooncatheter shaft. The balloon catheter shaft comprises an elongate tubularbody having a central lumen extending therethrough to place theinflatable balloon in fluid communication with a source of inflationmedia, which may be coupled to the proximal end of the shaft. A centralcore wire extends through at least a portion of the central lumen, andthrough the balloon, to support the distal end of the balloon. The corewire may extend distally beyond the balloon for a length of at leastabout 2 mm to 10 cm, and preferably at least about 3 cm to 5 cm toprovide a flexible advance segment.

The inside diameter of the central lumen is greater than the outsidediameter of the core wire, to provide an inflation lumen and enableinflation of the balloon.

The sealant 1516 is preferably provided with a central lumen such thatit can be pre-mounted on a distal end of the balloon catheter shaft,proximally of the inflatable balloon. The sealant 1516 may be formed asa cylindrical plug, having a central lumen extending therethrough.Alternatively, the sealant 1516 may be provided in a form of a sheet ormembrane, which can be wrapped in one, two, three, four, or more layersaround the catheter shaft.

Referring, for example, to FIGS. 21F and 21G, the sealant isprepositioned on the distal catheter shaft and spaced a short distancefrom the proximal surface of the inflated balloon. That space may bedimensioned to cooperate with the anticipated wall thickness of thevessel, such as is illustrated in FIG. 21G, so that the inflated ballooncan be positioned against the interior wall of the vessel and thesealant will be positioned directly outside of the puncture adjacent theoutside wall of the vessel. The space measured in an axial directionbetween the distal end of the sealant and the proximal surface of theballoon will typically be no greater than about 4 mm, and, in someembodiments, no greater than about 3 mm or 2 mm.

Using this construction, the sealant may be prepositioned on the ballooncatheter shaft at the point of manufacture, or, in any event, at theclinical site prior to introduction of the balloon catheter into thepatient. The balloon catheter and the sealant are thereafter guided as asingle unit by the sheath 1510, from outside of the patient, into theproximal end of the sheath 1510, and guided by the sheath 1510 to thevessel wall. The balloon may thereafter be inflated within the vessel,and the system may be proximally withdrawn as a unit without anyinternal relative motion between the balloon catheter and the sealantfrom the distal position illustrated in FIG. 21F to the proximal, seatedposition in FIG. 21G. Thereafter, proximal retraction of the outersleeve exposes the sealant.

EXAMPLES Example 1

Chitosan salt (chloride salt, Protasan UP CL 214 from FMC BioPolymer,Molecular Weight 150-400 kDa, degree of deacetylation >90%) was mixedwith PEG-ester (4-arm-10K-CM-HBA-NHS, MW 10 kDa) and PEG-amine(8-arm-20K-PEG-NH₃ ⁺Cl⁻, MW 20 kDa) precursors in the appropriatebuffers (phosphate and borate buffers, respectively) and allowed toreact to form hydrogels, which were subsequently frozen at about −37° C.and then allowed to gradually freeze dry over a period of about 20hours. The freeze dried hydrogels were then conditioned through varioushumidity and temperature steps to yield freeze dried hydrogels withstructural integrity able to be sliced into rectangular shapes (about 6mm by about 15 mm). Table 1 below summarizes the thickness and bloodswelling data of hydrogels synthesized by blending chitosan withPEG-ester and PEG-amine precursors in the appropriate buffers (Samples 1to 10), before sterilization, compared to a control sample (PEG onlyhydrogel) that does not contain chitosan and is also tested beforesterilization (Samples 11 and 12). The mole equivalent ratio ofPEG-ester to PEG-amine has been varied in this example, and was testedat a range of about 1 to about 1.5. Chitosan has been varied between 0to about 6.90/% by weight in this example. The blood swelling tests wereperformed by dipping the freeze dried hydrogels (pre-sterilization) inbovine blood at about 37° C. for about 45 seconds and measuring thepercentage of swelling by measuring the difference in weight before andafter dipping in the blood.

TABLE 1 PEG- PEG- Chitosan Final Sample Amine Ester Chloride Thickness %Swell in No. (g) (g) (g) (mm) bovine blood¹ 1 0.817 0.803 0.120 1.663025, 3114 2 0.817 0.803 0.120 1.83 2933, 2613 3 0.860 0.845 0.085 2.104532, 4552 4 0.860 0.845 0.085 2.12 4536, 3914 5 0.648 0.972 0.120 1.513062, 2660 6 0.648 0.972 0.120 1.64 2648, 2813 7 0.682 1.023 0.085 2.054103, 3756 8 0.682 1.023 0.085 2.13 3850, 4026 9 0.767 0.938 0.085 1.893347, 3280 10 0.767 0.938 0.085 1.71 3051, 2960 11 0.903 0.887 0 1.102566, 2436 12 0.903 0.887 0 1.17 2922, 2681 ¹Pre-sterile rectangular (6mm by 15 mm) freeze dried hydrogels were tested with two samples performulation tested for % of swelling in bovine blood.

The results of the Bovine Blood Swell are indicated in Table 1 above.Samples 11 and 12, which were made from PEG precursors only (no chitosanincorporated), demonstrate a substantial ability to swell upon contactwith blood. It is believed that this swelling ability of PEG onlyhydrogels is due to the porosity characteristics (size and number ofpores) that partially cross-linked PEG hydrogels can create upon freezedrying. The data in Table 1 demonstrates that pre-sterilization, freezedried PEG/Chitosan copolymer sealants (Samples 1 to 10) made bycovalently bonding chitosan with the PEG precursors can exhibit aswelling ability that is comparable to the swelling ability of thePEG-only hydrogels, independent of the amount of chitosan incorporated(for the ratios tested), or can even exceed the swelling ability ofPEG-only hydrogels.

Example 2

Chitosan salt (sodium salt from Xianju Tengwang) was mixed withPEG-ester (4-arm-10K-CM-HBA-NHS) and PEG-amine (8-arm-20K-PEG-NH3+Cl—)precursors in the appropriate buffers (phosphate and borate buffers,respectively) and reacted until a gel is formed. The resultant hydrogelwas frozen at about −37° C. and then allowed to gradually freeze dryover a period of about 20 hrs. The freeze dried hydrogels weresubsequently conditioned through various humidity and temperature stepsto yield freeze dried hydrogels with structural integrity allowing themto be manipulated (e.g., sliced, rolled and loaded on the distal end ofa delivery catheter (e.g., MYNXGRIP® catheter). Table 2 below summarizesthe amounts used and the thickness and swelling data of the finalhydrogels synthesized by blending chitosan with PEG-ester and PEG-amineprecursors in the appropriate buffers. The table below shows that freezedried hydrogels synthesized by covalently bonding chitosan with the PEGprecursors can substantially swell upon contact with bovine blood andthat the percent swell is comparable to the control samples.

TABLE 2 Sample Thickness No. Chitosan (soluble) (mm) % Swell² 1 Control¹1.68 3001, 3139 2 Control¹ 1.58 3336, 3230 3 Same as control add 0.5% wt2.36 3339, 3758 chitosan 4 Same as control add 0.5% wt 2.43 3670, 3257chitosan 5 Same as control add 1% wt 2.98 1277, 1055 chitosan ¹Controlcontains 0.903 g PEG-amine (8-arm-20K-PEG-NH3+Cl−) and 0.887 g PEG-ester(4-arm-10K-CM-HBA-NHS). ²Two samples from each hydrogel cake were testedfor % of swelling in bovine blood.

Example 3

Chitosan salt (chloride salt, Protasan UP CL 213 from FMC BioPolymer,Molecular Weight 150-400 kDa, degree of deacetylation 75-90%) was mixedwith PEG-ester (4-arm-10K-CM-HBA-NHS, MW 10 kDa) and PEG-amine(8-arm-20K-PEG-NH₃ ⁺Cl⁻, MW 20 kDa) precursors, at the amounts shown inTable 3 below, in the appropriate buffers (phosphate and borate buffers,respectively) and allowed to react to form hydrogels, which weresubsequently frozen at about −37° C. and then allowed to graduallyfreeze dry over a period of about 20 hours. The mole equivalent ratio ofPEG-ester to PEG-amine is about 1 in this example. The chitosan wasvaried between 0 to about 5.5% by weight in this example. The freezedried hydrogels were then conditioned through various humidity andtemperature steps to yield freeze dried hydrogels with structuralintegrity such that it is able to be sliced (about 6 mm by about 15 mmrectangles) and rolled into a cylindrical shape. Un-reacted PEG-esterand PEG-amine components (which are the same PEG components used for thefreeze-dried portion of the Hydrogel sealant with no chitosan) weremixed together (at a mole equivalent ratio of 1 to 1) by melting andapplied to the distal end of the freeze-dried sealant. The rolled freezedried hydrogels with the un-reacted PEG components on the distal endwere then loaded onto the distal end of a delivery catheter (i.e., a 6French extravascular delivery catheter, MYNXGRIP® Catheter).

The delivery catheters were then subject to sterilization by e-beam.After sterilization, the hydrogels were discharged from the catheterdevice by using a simulated technique as in an actual use of theextravascular delivery system to assess their blood swelling performancein bovine blood. The samples that were tested were chitosan withPEG-ester and PEG-amine precursors (Formulations 3-2 to 3-6) compared toa control sample (PEG only hydrogel) that did not contain chitosan(Formulation 3-1). The blood swelling test was performed by immersingthe freeze dried hydrogels (post-sterile) in bovine blood at about 37°C. for about 45 seconds and measuring the percentage of swelling bymeasuring the difference in weight before and after dipping in the blood(e.g., % Swell=(((Swelled weight of hydrogel−Excess FluidWeight)−Initial Hydrogel Weight)/Initial Hydrogel Weight)×100%; wherethe excess fluid weight is considered as the blood that is notincorporated within the hydrogel structure). The results of the bloodswelling test are reproduced below in Table 3.

TABLE 3 PEG- PEG- % Swell in Formulation Amine Ester Chitosan Thicknessbovine blood No. (g) (g) (g) (mm) (Avg + St. Dev.)¹ 3-1 0.865 0.925 01.10 1549 ± 239 3-2 0.858 0.907 0.025 2.10 NT² 3-3 0.850 0.890 0.0501.60  939 ± 191 3-4 0.844 0.886 0.060 1.40 1358 ± 196 3-5 0.834 0.8760.080 1.50 1389 ± 249 3-6 0.824 0.866 0.100 1.75  748 ± 169¹Post-sterile freeze dried hydrogels after loaded onto a 6Frextravascular delivery system; 10 samples per formulation were testedfor % of swelling in bovine blood. ²NT: Not tested. Formulation 3-2 wasnot tested for blood swelling because it could not be loaded onto theMYNXGRIP ® catheter system because of its thickness.

Formulation 3-1 (Control) from Table 3 above demonstrated a substantialability to swell upon contact with blood. The data for Formulations 3-3through 3-5 demonstrated that post-sterile freeze dried PEG/Chitosancopolymer sealants that were loaded onto a 6Fr extravascular deliverycatheter and then discharged can exhibit a swelling ability that iscomparable to the swelling ability of the PEG-only hydrogels. Althoughthe swelling ability of Formulation No. 3-6 was lower as compared to thecontrol sample, this value (about 750% swelling in blood) is alsoconsidered to have comparable swelling as to the control (FormulationNo. 3-1).

Example 4

Freeze dried PEG/Chitosan hydrogels were made as in Example 3 exceptthat the mole equivalent ratio of PEG-ester to PEG-amine was 1.1. Thehydrogels were rolled and loaded on the distal end of a deliverycatheter as before (e.g., 6Fr extravascular delivery catheter, MYNXGRIP®Catheter) and all catheters were sterilized by e-beam. The chitosan wasvaried between 0 to about 5.5% by weight. The blood swelling tests wereperformed as in Example 3. Formulation 4-1 was made from PEG precursorsonly (no chitosan incorporated), which is the control sample, andFormulations 4-2 to 4-6 were made with varying amounts of PEG/Chitosan,as shown in Table 4 below. The results of the blood swelling test arereproduced below in Table 4.

TABLE 4 PEG- PEG- % Swell in Sample Amine Ester Chitosan Thicknessbovine blood No. (g) (g) (g) (mm) (Avg + St. Dev.)¹ 4-1 0.865 0.925 01.10 1549 ± 239  4-2 0.827 0.938 0.025 2.10 NT² 4-3 0.815 0.925 0.0501.65 643 ± 107 4-4 0.810 0.920 0.060 1.90 NT² 4-5 0.801 0.909 0.080 1.40912 ± 207 4-6 0.792 0.898 0.100 1.60 973 ± 255 ¹Post-sterile freezedried hydrogels after loaded onto a 6Fr extravascular delivery system;10 samples per formulation were tested for % of swelling in bovineblood. ²NT: Not tested. Formulations 4-2 and 4-4 were not tested forblood swelling because it could not be loaded on the MYNXGRIP ® cathetersystem because of its thickness.

Formulation 4-1 (Control) demonstrated a substantial ability to swellupon contact with blood when loaded onto the 6Fr extravascular deliverycatheter and after sterilization. In evaluating Formulations 4-3, 4-5and 4-6, these samples demonstrated that post-sterilization, freezedried PEG/Chitosan copolymer sealants that have been loaded onto 6Frextravascular delivery catheters can exhibit a swelling ability that isconsidered to be comparable to that of the PEG-only hydrogels.

Example 5

The blood clotting ability of PEG/Chitosan copolymer hydrogels(Formulations 3-2 to 3-6 from Example 3) was compared with the bloodclotting ability of PEG-only hydrogels (control, Formulation 3-1 fromExample 3) before sterilization. The samples were prepared in advance ofperforming the blood clotting test by cutting the freeze-dried hydrogelsinto disks with a diameter of about 8 mm. In performing the bloodclotting test, the lyophilized disk samples were treated with bovinewhole blood (anticoagulated with Acid Citrate Dextrose—ACD) and CaCl₂and put in the oven at about 37° C. for about 10 minutes as part of theincubation period. After the incubation period, red blood cells thatwere not trapped in the clot were hemolyzed in DI water and the UVabsorbance of the resulting hemoglobin solution was measured at awavelength of about 540 nm. The higher absorbance value of thehemoglobin solution indicates a slower clotting rate, while a lowerabsorbance value indicates a faster clotting rate. Table 5 belowsummarizes the results of the blood clotting test of hydrogels made withPEG-only (Formulation 3-1, Control) compared to the hydrogels made withPEG/Chitosan copolymers (Formulation numbers 3-2 through 3-6).

TABLE 5 PEG- PEG- UV absorbance Formulation Amine Ester ChitosanThickness at 540 nm No. (g) (g) (g) (mm) (Avg + St. Dev.)¹ 3-1 0.8650.925 0 1.10 0.170 ± 0.040 3-2 0.858 0.907 0.025 2.10 0.036 ± 0.020 3-30.850 0.890 0.050 1.60 0.033 ± 0.017 3-4 0.844 0.886 0.060 1.40 0.055 ±0.031 3-5 0.834 0.876 0.080 1.50 0.045 ± 0.034 3-6 0.824 0.866 0.1001.75 0.006 ± 0.006 ¹Three samples from each hydrogel formulation weretested.

From the results, it can be seen that Formulations 3-2 to 3-6, whichcomprise the PEG/Chitosan copolymers, result in faster clotting ratescompared to hydrogels that comprise only PEG, as exhibited by the lowerUV absorbance rates of the PEG/Chitosan samples. All of the PEG/Chitosancopolymers tested indicate a substantial improvement in the bloodclotting ability compared to the PEG-only Control sample, independent ofthe amount of Chitosan incorporated.

Example 6

Similar to Example 5, the blood clotting ability of pre-sterilePEG/Chitosan copolymer hydrogels (Formulations 4-2 to 4-6 from Example4, prior to sterilization) was compared to a pre-sterile PEG-onlyhydrogel (control, Formulation 4-1 from Example 4, prior tosterilization) using the blood clotting test explained above in Example5. The test parameters of the blood clotting test were kept the same asin Example 5. Table 6 below summarizes results of the blot clotting testof hydrogels manufactured with PEG-only (Formulation 4-1, Control)compared to hydrogels manufactured with PEG/Chitosan copolymers(Formulation numbers 4-2 through 4-6).

TABLE 6 PEG- PEG- UV absorbance Formulation Amine Ester ChitosanThickness at 540 nm No. (g) (g) (g) (mm) (Avg + St. Dev.)¹ 4-1 0.8650.925 0 1.10 0.201 ± 0.045 4-2 0.827 0.938 0.025 2.10 0.003 ± 0.005 4-30.815 0.925 0.050 1.65 0.033 ± 0.010 4-4 0.810 0.920 0.060 1.90 0.008 ±0.006 4-5 0.801 0.909 0.080 1.40 0.083 ± 0.045 4-6 0.792 0.898 0.1001.60 0.034 ± 0.027 ¹Three samples from each hydrogel formulation weretested.

Table 6 shows that the hydrogels that comprise PEG/Chitosan copolymers(Formulations 4-2 to 4-6) result in faster clotting rates due to thelower UV absorbance values as compared to the hydrogels that comprisePEG only (Formulation 4-1, Control). All of the PEG/Chitosan copolymerstested indicate a substantial improvement in the blood clotting abilitywhen compared to PEG-only, independent of the amount of Chitosanincorporated.

Example 7

Similar to Example 5, the blood clotting ability of PEG only hydrogels(no chitosan incorporated) of various thicknesses was tested in order toevaluate the effect of thickness on the blood clotting ability of thehydrogel disks (diameter of about 8 mm) before sterilization. The testparameters of the blood clotting test were kept the same as in Example5. Table 7 below summarizes results of the blot clotting test ofhydrogels manufactured with PEG-only (Controls) of various thicknessesas shown below in the table.

TABLE 7 PEG- PEG- UV absorbance Formulation Amine Ester ChitosanThickness at 540 nm No. (g) (g) (g) (mm) (Avg + St. Dev.)¹ 7-1 0.7880.814 0 0.80 0.226 ± 0.040 7-2 0.788 0.814 0 0.99 0.227 ± 0.084 7-30.881 0.909 0 1.00 0.225 ± 0.008 7-4 0.881 0.909 0 1.22 0.113 ± 0.0237-5 0.873 0.917 0 1.47 0.156 ± 0.025 ¹Three samples from each hydrogelformulation were tested.

Table 7 indicates that as expected the blood clotting ability ofPEG-only hydrogels increases with increasing thickness up to a certainpoint and then the blood clotting ability starts to decrease, unaffectedby the thicker sample pieces. However, the effect of thickness on theblood clotting ability of the hydrogel disks (without chitosan) is notas significant as is the incorporation of chitosan into these hydrogelsealants. The blood clotting test data of hydrogels of similar thicknessof PEG/Chitosan hydrogels as compared to PEG-only hydrogels (e.g.Formulation 7-5 from Table 7 above compared to Formulations 3-4 and 4-5from Tables 5 and 6 respectively which are all about 1.4 mm thick) showthat the formulations that contain chitosan result in substantiallyfaster clotting rates.

Example 8

Hydrogel prototypes comprising PEG/Chitosan copolymer sealants as madein Example 3, Formulation 3-3, were loaded onto a 6 French deliverysystem (i.e., the MYNXGRIP® vascular closure device) and tested in anovine model. The PEG/chitosan sealants were sized small enough to fit,i.e., be loaded, onto the 6Fr delivery device. Seven femoral accesssites were sealed using the PEG/Chitosan copolymer sealants in thisstudy to assess their performance in femoral punctures that range insize from small bore sizes to large bore sizes. Standard catheterizationtechniques were followed including contemporary anticoagulation.Procedural sheaths utilized were sized to create femoral arterypunctures from 7Fr, 8.5Fr, 9Fr, and 10Fr. The 6Fr delivery systemsloaded with the PEG/chitosan sealants were each deployed into one of theseven punctures. All deployments of the PEG/chitosan sealants(Formulation 3-3) using the 6Fr delivery systems were clinicallysuccessful, e.g., the PEG/chitosan sealed the puncture. These resultsdemonstrate that arterial closure (up to a puncture size from a 10Frsheath) can be feasible using a 6Fr-compatible PEG/Chitosan sealant. The6 French delivery device was utilized to show that a large bore puncturecan be closed with a small bore device, i.e., a device that is sizedsmaller than the size of the puncture. However, a delivery device sizedlarger than 6 Fr may also be used and, in particular, a delivery devicesized similar to the size of the puncture may of course be used.

It is contemplated that various combinations or subcombinations of thespecific features and aspects of the embodiments disclosed above may bemade and still fall within one or more of the embodiments herein.Further, the disclosure herein of any particular feature, aspect,method, property, characteristic, quality, attribute, element, or thelike in connection with an embodiment can be used in all otherembodiments set forth herein. Accordigly, it should be understood thatvarious features and aspects of the disclosed embodiments can becombined with or substituted for one another in order to form varyingmodes of the disclosed embodiments. Thus, it is intended that the scopeof the present embodiments herein disclosed should not be limited by theparticular disclosed embodiments described above. Moreover, while thesealant, apparatus and/or method disclosed herein can be susceptible tovarious modifications, and alternative forms, specific examples thereofhave been shown in the drawings and are herein described in detail. Itshould be understood, however, that the sealant, device and method arenot to be limited to the particular forms or methods disclosed, but tothe contrary, can cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the various embodiments describedand the appended claims. Any methods disclosed herein need not beperformed in the order recited. The methods disclosed herein includecertain actions taken by a practitioner; however, they can also includeany third-party instruction of those actions, either expressly or byimplication. For example, actions such as “inserting a vascular sealantto seal a vascular puncture” include “instructing the insertion ofvascular sealant to seal a vascular puncture.”

The ranges disclosed herein also encompass any and all overlap,sub-ranges, and combinations thereof. Language such as “up to,” “atleast,” “greater than,” “less than,” “between,” and the like includesthe number recited. Numbers preceded by a term such as “about” or“approximately” include the recited numbers. For example, “about 10nanometers” includes “10 nanometers.”

1. A sealant for sealing a puncture through tissue, comprising: a first section formed from a freeze-dried hydrogel, wherein the first section expands when exposed to physiological fluid within a puncture; and wherein the first section comprises a hydrogel comprising chitosan bound to at least one polymer, wherein, upon exposure to an aqueous physiological fluid, the hydrogel expands and seals the puncture through the tissue.
 2. The sealant of claim 1, wherein the chitosan comprises chitosan that is at least partially deacetylated.
 3. The sealant of claim 2, wherein the chitosan has a degree of deacetylation of at least 60%.
 4. The sealant of claim 1, wherein the chitosan has a molecular weight between about 10 kilodaltons and about 600 kilodaltons.
 5. The sealant of claim 1, wherein the chitosan is selected from the group consisting of free chitosan, chitosan chloride, chitosan glutamate, chitosan acetate, chitosan dicarboxylic acid salts, chitosan adipate, chitosan succinate, chitosan fumarate, and combinations thereof.
 6. The sealant of claim 1, wherein the at least one polymer comprises one or more of a polyethylene glycol polymer chain with side group functionality.
 7. The sealant of claim 6, wherein the at least one polymer comprises one or more of an amine modified polyethylene glycol and an ester modified polyethylene glycol.
 8. The sealant of claim 1, wherein the chitosan is bound to the at least one polymer by a covalent bond.
 9. The sealant of claim 1, wherein the chitosan is bound to the at least one polymer by a non-covalent bond.
 10. The sealant of claim 1, wherein the at least one polymer comprises cross-linked polyethylene glycol that is bound to the chitosan.
 11. The sealant of claim 1, wherein the first section comprises between about 0.1% and about 30% (by weight) chitosan.
 12. The sealant of claim 1, wherein the at least one polymer comprises polyethylene glycol-amine (PEG-amine) and polyethylene glycol-ester (PEG-ester) and wherein a molar ratio of PEG-amine to PEG-ester is between 4 to 1 and 1 to
 4. 13. The sealant of claim 1, wherein the at least one polymer comprises polyethylene glycol-amine and polyethylene glycol-ester and wherein an equivalent ratio of active group sites of PEG-amine to PEG-ester is between about 0.1 to about
 4. 14. The sealant of claim 1, wherein the at least one polymer comprises polyethylene glycol-amine and polyethylene glycol-ester and wherein a molar ratio of chitosan to PEG-ester is between about 0.0005 to about 0.01.
 15. The sealant of claim 1, wherein the at least one polymer comprises polyethylene glycol-amine and polyethylene glycol-ester and wherein an equivalent ratio of active group sites of chitosan to PEG-ester is between about 0.1 to about
 5. 16. The sealant of claim 1, wherein the sealant comprises a second section extending from the distal end of the first section.
 17. The sealant of claim 16, wherein the second section comprises non-cross-linked precursors.
 18. The sealant of claim 17, wherein the non-crosslinked precursors comprise polyethylene glycol-amine and polyethylene glycol-ester.
 19. The sealant of claim 16, wherein the second section further comprises chitosan.
 20. The sealant of claim 19, wherein the second section comprises a mixture of non-cross-linked polyethylene glycols bound to the chitosan.
 21. The sealant of claim 16, wherein the second section further comprises one or more reinforcement elements with hemostatic properties selected from the group consisting of chitosan reinforcing fibers, chitosan mesh, chitosan particles, or combinations thereof.
 22. The sealant of claim 16, wherein the second section comprises between about 1% and about 80% (by weight) chitosan.
 23. The sealant of claim 19, wherein the chitosan is in the form of particles that are incorporated into the second section.
 24. A sealant according to claim 1, wherein the sealant is configured to seal a vascular puncture, wherein exposure of the sealant to an aqueous physiological fluid causes the sealant to expand, and wherein the sealant has hemostatic and pro-coagulative properties.
 25. The sealant according to claim 16, wherein the first section has a length between the proximal and distal ends between about 1 and about 20 millimeters, and wherein the second section has a length between about 0.5 and about 5 millimeters.
 26. The sealant according to claim 16, wherein the first and second sections have a substantially uniform outer cross-section along their lengths between about 1 and about 8 millimeters.
 27. The sealant according to claim 26, wherein the first and second sections are suitable for expansion in the dimension of the outer cross section of the sealant of at least 50%. 28-35. (canceled)
 36. A method of making a sealant for sealing a puncture through tissue, the method comprising: forming an elongate first section including a proximal end, a distal end, and a cross-section sized for delivery into a puncture through tissue, the first section formed from a freeze-dried hydrogel comprising polyethylene glycol (PEG) and chitosan, the hydrogel capable of expanding when exposed to a physiological fluid within the puncture; and applying a second section to the distal end of the first section, the second section comprising a plurality of non-crosslinked PEG precursors, the precursors remaining in an unreactive state until exposed to the physiological fluid within the puncture, whereupon the precursors undergo in-situ crosslinking with one another and to bond to the second section. 37-41. (canceled)
 42. The sealant of claim 1, wherein the sealant is provided in a device having a diameter that is smaller than a diameter of the puncture.
 43. The sealant of claim 1, wherein the first section consists essentially of chitosan bound to at least one polymer.
 44. The sealant of claim 1, wherein the first section further comprises a pH adjusting agent.
 45. The sealant of claim 16, wherein the second section does not include chitosan.
 46. The sealant of claim 16, wherein the second section consists essentially of the plurality of non-cross-linked precursors. 